codegenarmarch.cpp

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

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XX                        ARM/ARM64 Code Generator Common Code               XX
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*/
#include "jitpch.h"
#ifdef _MSC_VER
#pragma hdrstop
#endif

#ifdef TARGET_ARMARCH // This file is ONLY used for ARM and ARM64 architectures

#include "codegen.h"
#include "lower.h"
#include "gcinfo.h"
#include "emit.h"
#include "patchpointinfo.h"

//------------------------------------------------------------------------
// genStackPointerConstantAdjustment: add a specified constant value to the stack pointer.
// No probe is done.
//
// Arguments:
//    spDelta                 - the value to add to SP. Must be negative or zero.
//    regTmp                  - an available temporary register that is used if 'spDelta' cannot be encoded by
//                              'sub sp, sp, #spDelta' instruction.
//                              Can be REG_NA if the caller knows for certain that 'spDelta' fits into the immediate
//                              value range.
//
// Return Value:
//    None.
//
void CodeGen::genStackPointerConstantAdjustment(ssize_t spDelta, regNumber regTmp)
{
    assert(spDelta < 0);

    // We assert that the SP change is less than one page. If it's greater, you should have called a
    // function that does a probe, which will in turn call this function.
    assert((target_size_t)(-spDelta) <= compiler->eeGetPageSize());

#ifdef TARGET_ARM64
    genInstrWithConstant(INS_sub, EA_PTRSIZE, REG_SPBASE, REG_SPBASE, -spDelta, regTmp);
#else
    genInstrWithConstant(INS_sub, EA_PTRSIZE, REG_SPBASE, REG_SPBASE, -spDelta, INS_FLAGS_DONT_CARE, regTmp);
#endif
}

//------------------------------------------------------------------------
// genStackPointerConstantAdjustmentWithProbe: add a specified constant value to the stack pointer,
// and probe the stack as appropriate. Should only be called as a helper for
// genStackPointerConstantAdjustmentLoopWithProbe.
//
// Arguments:
//    spDelta                 - the value to add to SP. Must be negative or zero. If zero, the probe happens,
//                              but the stack pointer doesn't move.
//    regTmp                  - temporary register to use as target for probe load instruction
//
// Return Value:
//    None.
//
void CodeGen::genStackPointerConstantAdjustmentWithProbe(ssize_t spDelta, regNumber regTmp)
{
    GetEmitter()->emitIns_R_R_I(INS_ldr, EA_4BYTE, regTmp, REG_SP, 0);
    genStackPointerConstantAdjustment(spDelta, regTmp);
}

//------------------------------------------------------------------------
// genStackPointerConstantAdjustmentLoopWithProbe: Add a specified constant value to the stack pointer,
// and probe the stack as appropriate. Generates one probe per page, up to the total amount required.
// This will generate a sequence of probes in-line.
//
// Arguments:
//    spDelta                 - the value to add to SP. Must be negative.
//    regTmp                  - temporary register to use as target for probe load instruction
//
// Return Value:
//    Offset in bytes from SP to last probed address.
//
target_ssize_t CodeGen::genStackPointerConstantAdjustmentLoopWithProbe(ssize_t spDelta, regNumber regTmp)
{
    assert(spDelta < 0);

    const target_size_t pageSize = compiler->eeGetPageSize();

    ssize_t spRemainingDelta = spDelta;
    do
    {
        ssize_t spOneDelta = -(ssize_t)min((target_size_t)-spRemainingDelta, pageSize);
        genStackPointerConstantAdjustmentWithProbe(spOneDelta, regTmp);
        spRemainingDelta -= spOneDelta;
    } while (spRemainingDelta < 0);

    // What offset from the final SP was the last probe? This depends on the fact that
    // genStackPointerConstantAdjustmentWithProbe() probes first, then does "SUB SP".
    target_size_t lastTouchDelta = (target_size_t)(-spDelta) % pageSize;
    if ((lastTouchDelta == 0) || (lastTouchDelta + STACK_PROBE_BOUNDARY_THRESHOLD_BYTES > pageSize))
    {
        // We haven't probed almost a complete page. If lastTouchDelta==0, then spDelta was an exact
        // multiple of pageSize, which means we last probed exactly one page back. Otherwise, we probed
        // the page, but very far from the end. If the next action on the stack might subtract from SP
        // first, before touching the current SP, then we do one more probe at the very bottom. This can
        // happen on x86, for example, when we copy an argument to the stack using a "SUB ESP; REP MOV"
        // strategy.

        GetEmitter()->emitIns_R_R_I(INS_ldr, EA_4BYTE, regTmp, REG_SP, 0);
        lastTouchDelta = 0;
    }

    return lastTouchDelta;
}

//------------------------------------------------------------------------
// genCodeForTreeNode Generate code for a single node in the tree.
//
// Preconditions:
//    All operands have been evaluated.
//
void CodeGen::genCodeForTreeNode(GenTree* treeNode)
{
    regNumber targetReg  = treeNode->GetRegNum();
    var_types targetType = treeNode->TypeGet();
    emitter*  emit       = GetEmitter();

#ifdef DEBUG
    // Validate that all the operands for the current node are consumed in order.
    // This is important because LSRA ensures that any necessary copies will be
    // handled correctly.
    lastConsumedNode = nullptr;
    if (compiler->verbose)
    {
        unsigned seqNum = treeNode->gtSeqNum; // Useful for setting a conditional break in Visual Studio
        compiler->gtDispLIRNode(treeNode, "Generating: ");
    }
#endif // DEBUG

    // Is this a node whose value is already in a register?  LSRA denotes this by
    // setting the GTF_REUSE_REG_VAL flag.
    if (treeNode->IsReuseRegVal())
    {
        genCodeForReuseVal(treeNode);
        return;
    }

    // contained nodes are part of their parents for codegen purposes
    // ex : immediates, most LEAs
    if (treeNode->isContained())
    {
        return;
    }

    switch (treeNode->gtOper)
    {
        case GT_START_NONGC:
            GetEmitter()->emitDisableGC();
            break;

        case GT_START_PREEMPTGC:
            // Kill callee saves GC registers, and create a label
            // so that information gets propagated to the emitter.
            gcInfo.gcMarkRegSetNpt(RBM_INT_CALLEE_SAVED);
            genDefineTempLabel(genCreateTempLabel());
            break;

        case GT_PROF_HOOK:
            // We should be seeing this only if profiler hook is needed
            noway_assert(compiler->compIsProfilerHookNeeded());

#ifdef PROFILING_SUPPORTED
            // Right now this node is used only for tail calls. In future if
            // we intend to use it for Enter or Leave hooks, add a data member
            // to this node indicating the kind of profiler hook. For example,
            // helper number can be used.
            genProfilingLeaveCallback(CORINFO_HELP_PROF_FCN_TAILCALL);
#endif // PROFILING_SUPPORTED
            break;

        case GT_LCLHEAP:
            genLclHeap(treeNode);
            break;

        case GT_CNS_INT:
        case GT_CNS_DBL:
        case GT_CNS_VEC:
            genSetRegToConst(targetReg, targetType, treeNode);
            genProduceReg(treeNode);
            break;

        case GT_NOT:
        case GT_NEG:
            genCodeForNegNot(treeNode);
            break;

#if defined(TARGET_ARM64)
        case GT_BSWAP:
        case GT_BSWAP16:
            genCodeForBswap(treeNode);
            break;
#endif // defined(TARGET_ARM64)

        case GT_MOD:
        case GT_UMOD:
        case GT_DIV:
        case GT_UDIV:
            genCodeForDivMod(treeNode->AsOp());
            break;

        case GT_OR:
        case GT_XOR:
        case GT_AND:
        case GT_AND_NOT:
            assert(varTypeIsIntegralOrI(treeNode));

            FALLTHROUGH;

#if !defined(TARGET_64BIT)
        case GT_ADD_LO:
        case GT_ADD_HI:
        case GT_SUB_LO:
        case GT_SUB_HI:
#endif // !defined(TARGET_64BIT)

        case GT_ADD:
        case GT_SUB:
        case GT_MUL:
            genConsumeOperands(treeNode->AsOp());
            genCodeForBinary(treeNode->AsOp());
            break;

        case GT_LSH:
        case GT_RSH:
        case GT_RSZ:
        // case GT_ROL: // No ROL instruction on ARM; it has been lowered to ROR.
        case GT_ROR:
            genCodeForShift(treeNode);
            break;

#if !defined(TARGET_64BIT)

        case GT_LSH_HI:
        case GT_RSH_LO:
            genCodeForShiftLong(treeNode);
            break;

#endif // !defined(TARGET_64BIT)

        case GT_CAST:
            genCodeForCast(treeNode->AsOp());
            break;

        case GT_BITCAST:
            genCodeForBitCast(treeNode->AsOp());
            break;

        case GT_LCL_ADDR:
            genCodeForLclAddr(treeNode->AsLclFld());
            break;

        case GT_LCL_FLD:
            genCodeForLclFld(treeNode->AsLclFld());
            break;

        case GT_LCL_VAR:
            genCodeForLclVar(treeNode->AsLclVar());
            break;

        case GT_STORE_LCL_FLD:
            genCodeForStoreLclFld(treeNode->AsLclFld());
            break;

        case GT_STORE_LCL_VAR:
            genCodeForStoreLclVar(treeNode->AsLclVar());
            break;

        case GT_RETFILT:
        case GT_RETURN:
            genReturn(treeNode);
            break;

#ifdef SWIFT_SUPPORT
        case GT_SWIFT_ERROR_RET:
            genSwiftErrorReturn(treeNode);
            break;
#endif // SWIFT_SUPPORT

        case GT_LEA:
            // If we are here, it is the case where there is an LEA that cannot be folded into a parent instruction.
            genLeaInstruction(treeNode->AsAddrMode());
            break;

        case GT_INDEX_ADDR:
            genCodeForIndexAddr(treeNode->AsIndexAddr());
            break;

        case GT_IND:
            genCodeForIndir(treeNode->AsIndir());
            break;

        case GT_MUL_LONG:
            genCodeForMulLong(treeNode->AsOp());
            break;

#ifdef TARGET_ARM64
        case GT_INC_SATURATE:
            genCodeForIncSaturate(treeNode);
            break;

        case GT_MULHI:
            genCodeForMulHi(treeNode->AsOp());
            break;

        case GT_SWAP:
            genCodeForSwap(treeNode->AsOp());
            break;

        case GT_BFIZ:
            genCodeForBfiz(treeNode->AsOp());
            break;
#endif // TARGET_ARM64

        case GT_JMP:
            genJmpMethod(treeNode);
            break;

        case GT_CKFINITE:
            genCkfinite(treeNode);
            break;

        case GT_INTRINSIC:
            genIntrinsic(treeNode->AsIntrinsic());
            break;

#ifdef FEATURE_HW_INTRINSICS
        case GT_HWINTRINSIC:
            genHWIntrinsic(treeNode->AsHWIntrinsic());
            break;
#endif // FEATURE_HW_INTRINSICS

        case GT_EQ:
        case GT_NE:
        case GT_LT:
        case GT_LE:
        case GT_GE:
        case GT_GT:
        case GT_TEST_NE:
        case GT_TEST_EQ:
        case GT_CMP:
        case GT_TEST:
            genConsumeOperands(treeNode->AsOp());
            genCodeForCompare(treeNode->AsOp());
            break;

#ifdef TARGET_ARM64
        case GT_SELECT_NEG:
        case GT_SELECT_INV:
        case GT_SELECT_INC:
        case GT_SELECT:
            genCodeForSelect(treeNode->AsConditional());
            break;

        case GT_SELECT_NEGCC:
        case GT_SELECT_INVCC:
        case GT_SELECT_INCCC:
        case GT_SELECTCC:
            genCodeForSelect(treeNode->AsOp());
            break;

        case GT_JCMP:
        case GT_JTEST:
            genCodeForJumpCompare(treeNode->AsOpCC());
            break;

        case GT_CCMP:
            genCodeForCCMP(treeNode->AsCCMP());
            break;
#endif // TARGET_ARM64

        case GT_JTRUE:
            genCodeForJTrue(treeNode->AsOp());
            break;

        case GT_JCC:
            genCodeForJcc(treeNode->AsCC());
            break;

        case GT_SETCC:
            genCodeForSetcc(treeNode->AsCC());
            break;

        case GT_RETURNTRAP:
            genCodeForReturnTrap(treeNode->AsOp());
            break;

        case GT_STOREIND:
            genCodeForStoreInd(treeNode->AsStoreInd());
            break;

        case GT_COPY:
            // This is handled at the time we call genConsumeReg() on the GT_COPY
            break;

        case GT_FIELD_LIST:
            // Should always be marked contained.
            assert(!"LIST, FIELD_LIST nodes should always be marked contained.");
            break;

        case GT_PUTARG_STK:
            genPutArgStk(treeNode->AsPutArgStk());
            break;

        case GT_PUTARG_REG:
            genPutArgReg(treeNode->AsOp());
            break;

        case GT_PUTARG_SPLIT:
            genPutArgSplit(treeNode->AsPutArgSplit());
            break;

        case GT_CALL:
            genCall(treeNode->AsCall());
            break;

        case GT_MEMORYBARRIER:
        {
            CodeGen::BarrierKind barrierKind =
                treeNode->gtFlags & GTF_MEMORYBARRIER_LOAD ? BARRIER_LOAD_ONLY : BARRIER_FULL;

            instGen_MemoryBarrier(barrierKind);
            break;
        }

#ifdef TARGET_ARM64
        case GT_XCHG:
        case GT_XORR:
        case GT_XAND:
        case GT_XADD:
            genLockedInstructions(treeNode->AsOp());
            break;

        case GT_CMPXCHG:
            genCodeForCmpXchg(treeNode->AsCmpXchg());
            break;
#endif // TARGET_ARM64

#ifdef SWIFT_SUPPORT
        case GT_SWIFT_ERROR:
            genCodeForSwiftErrorReg(treeNode);
            break;
#endif // SWIFT_SUPPORT

        case GT_RELOAD:
            // do nothing - reload is just a marker.
            // The parent node will call genConsumeReg on this which will trigger the unspill of this node's child
            // into the register specified in this node.
            break;

        case GT_NOP:
            break;

        case GT_KEEPALIVE:
            if (treeNode->AsOp()->gtOp1->isContained())
            {
                // For this case we simply need to update the lifetime of the local.
                genUpdateLife(treeNode->AsOp()->gtOp1);
            }
            else
            {
                genConsumeReg(treeNode->AsOp()->gtOp1);
            }
            break;

        case GT_NO_OP:
            instGen(INS_nop);
            break;

        case GT_BOUNDS_CHECK:
            genRangeCheck(treeNode);
            break;

        case GT_PHYSREG:
            genCodeForPhysReg(treeNode->AsPhysReg());
            break;

        case GT_NULLCHECK:
            genCodeForNullCheck(treeNode->AsIndir());
            break;

        case GT_CATCH_ARG:

            noway_assert(handlerGetsXcptnObj(compiler->compCurBB->bbCatchTyp));

            /* Catch arguments get passed in a register. genCodeForBBlist()
               would have marked it as holding a GC object, but not used. */

            noway_assert(gcInfo.gcRegGCrefSetCur & RBM_EXCEPTION_OBJECT);
            genConsumeReg(treeNode);
            break;

        case GT_PINVOKE_PROLOG:
            noway_assert(((gcInfo.gcRegGCrefSetCur | gcInfo.gcRegByrefSetCur) &
                          ~fullIntArgRegMask(compiler->info.compCallConv)) == 0);

#ifdef PSEUDORANDOM_NOP_INSERTION
            // the runtime side requires the codegen here to be consistent
            emit->emitDisableRandomNops();
#endif // PSEUDORANDOM_NOP_INSERTION
            break;

        case GT_LABEL:
            genPendingCallLabel = genCreateTempLabel();
#if defined(TARGET_ARM)
            genMov32RelocatableDisplacement(genPendingCallLabel, targetReg);
#else
            emit->emitIns_R_L(INS_adr, EA_PTRSIZE, genPendingCallLabel, targetReg);
#endif
            break;

        case GT_STORE_BLK:
            genCodeForStoreBlk(treeNode->AsBlk());
            break;

        case GT_JMPTABLE:
            genJumpTable(treeNode);
            break;

        case GT_SWITCH_TABLE:
            genTableBasedSwitch(treeNode);
            break;

#ifdef TARGET_ARM
        case GT_LONG:
            assert(treeNode->isUsedFromReg());
            genConsumeRegs(treeNode);
            break;
#endif // TARGET_ARM

        case GT_IL_OFFSET:
            // Do nothing; these nodes are simply markers for debug info.
            break;

        default:
        {
            unreached();
        }
        break;
    }
}

//---------------------------------------------------------------------
// genSetGSSecurityCookie: Set the "GS" security cookie in the prolog.
//
// Arguments:
//     initReg        - register to use as a scratch register
//     pInitRegZeroed - OUT parameter. *pInitRegZeroed is set to 'false' if and only if
//                      this call sets 'initReg' to a non-zero value.
//
// Return Value:
//     None
//
void CodeGen::genSetGSSecurityCookie(regNumber initReg, bool* pInitRegZeroed)
{
    assert(compiler->compGeneratingProlog);

    if (!compiler->getNeedsGSSecurityCookie())
    {
        return;
    }

    if (compiler->opts.IsOSR() && compiler->info.compPatchpointInfo->HasSecurityCookie())
    {
        // Security cookie is on original frame and was initialized there.
        return;
    }

    if (compiler->gsGlobalSecurityCookieAddr == nullptr)
    {
        noway_assert(compiler->gsGlobalSecurityCookieVal != 0);
        // initReg = #GlobalSecurityCookieVal; [frame.GSSecurityCookie] = initReg
        instGen_Set_Reg_To_Imm(EA_PTRSIZE, initReg, compiler->gsGlobalSecurityCookieVal);
        GetEmitter()->emitIns_S_R(INS_str, EA_PTRSIZE, initReg, compiler->lvaGSSecurityCookie, 0);
    }
    else
    {
        instGen_Set_Reg_To_Imm(EA_PTR_DSP_RELOC, initReg, (ssize_t)compiler->gsGlobalSecurityCookieAddr,
                               INS_FLAGS_DONT_CARE DEBUGARG((size_t)THT_SetGSCookie) DEBUGARG(GTF_EMPTY));
        GetEmitter()->emitIns_R_R_I(INS_ldr, EA_PTRSIZE, initReg, initReg, 0);
        regSet.verifyRegUsed(initReg);
        GetEmitter()->emitIns_S_R(INS_str, EA_PTRSIZE, initReg, compiler->lvaGSSecurityCookie, 0);
    }

    *pInitRegZeroed = false;
}

//------------------------------------------------------------------------
// genEmitGSCookieCheck: Generate code to check that the GS cookie
// wasn't thrashed by a buffer overrun.
//
void CodeGen::genEmitGSCookieCheck(bool pushReg)
{
    noway_assert(compiler->gsGlobalSecurityCookieAddr || compiler->gsGlobalSecurityCookieVal);

    // Make sure that the return register is reported as live GC-ref so that any GC that kicks in while
    // executing GS cookie check will not collect the object pointed to by REG_INTRET (R0).
    if (!pushReg && (compiler->info.compRetNativeType == TYP_REF))
        gcInfo.gcRegGCrefSetCur |= RBM_INTRET;

    // We need two temporary registers, to load the GS cookie values and compare them. We can't use
    // any argument registers if 'pushReg' is true (meaning we have a JMP call). They should be
    // callee-trash registers, which should not contain anything interesting at this point.
    // We don't have any IR node representing this check, so LSRA can't communicate registers
    // for us to use.

    regNumber regGSConst = REG_GSCOOKIE_TMP_0;
    regNumber regGSValue = REG_GSCOOKIE_TMP_1;

    if (compiler->gsGlobalSecurityCookieAddr == nullptr)
    {
        // load the GS cookie constant into a reg
        //
        instGen_Set_Reg_To_Imm(EA_PTRSIZE, regGSConst, compiler->gsGlobalSecurityCookieVal);
    }
    else
    {
        // Ngen case - GS cookie constant needs to be accessed through an indirection.
        instGen_Set_Reg_To_Imm(EA_HANDLE_CNS_RELOC, regGSConst, (ssize_t)compiler->gsGlobalSecurityCookieAddr,
                               INS_FLAGS_DONT_CARE DEBUGARG((size_t)THT_GSCookieCheck) DEBUGARG(GTF_EMPTY));
        GetEmitter()->emitIns_R_R_I(INS_ldr, EA_PTRSIZE, regGSConst, regGSConst, 0);
    }
    // Load this method's GS value from the stack frame
    GetEmitter()->emitIns_R_S(INS_ldr, EA_PTRSIZE, regGSValue, compiler->lvaGSSecurityCookie, 0);
    // Compare with the GC cookie constant
    GetEmitter()->emitIns_R_R(INS_cmp, EA_PTRSIZE, regGSConst, regGSValue);

    BasicBlock* gsCheckBlk = genCreateTempLabel();
    inst_JMP(EJ_eq, gsCheckBlk);
    // regGSConst and regGSValue aren't needed anymore, we can use them for helper call
    genEmitHelperCall(CORINFO_HELP_FAIL_FAST, 0, EA_UNKNOWN, regGSConst);
    genDefineTempLabel(gsCheckBlk);
}

//---------------------------------------------------------------------
// genIntrinsic - generate code for a given intrinsic
//
// Arguments
//    treeNode - the GT_INTRINSIC node
//
// Return value:
//    None
//
void CodeGen::genIntrinsic(GenTreeIntrinsic* treeNode)
{
    // Both operand and its result must be of the same floating point type.
    GenTree* srcNode = treeNode->gtGetOp1();

#ifdef DEBUG
    if ((treeNode->gtIntrinsicName > NI_SYSTEM_MATH_START) && (treeNode->gtIntrinsicName < NI_SYSTEM_MATH_END))
    {
        assert(varTypeIsFloating(srcNode));
        assert(srcNode->TypeGet() == treeNode->TypeGet());
    }
#endif // DEBUG

    // Handle intrinsics that can be implemented by target-specific instructions
    switch (treeNode->gtIntrinsicName)
    {
        case NI_System_Math_Abs:
            genConsumeOperands(treeNode->AsOp());
            GetEmitter()->emitInsBinary(INS_ABS, emitActualTypeSize(treeNode), treeNode, srcNode);
            break;

#ifdef TARGET_ARM64
        case NI_System_Math_Ceiling:
            genConsumeOperands(treeNode->AsOp());
            GetEmitter()->emitInsBinary(INS_frintp, emitActualTypeSize(treeNode), treeNode, srcNode);
            break;

        case NI_System_Math_Floor:
            genConsumeOperands(treeNode->AsOp());
            GetEmitter()->emitInsBinary(INS_frintm, emitActualTypeSize(treeNode), treeNode, srcNode);
            break;

        case NI_System_Math_Truncate:
            genConsumeOperands(treeNode->AsOp());
            GetEmitter()->emitInsBinary(INS_frintz, emitActualTypeSize(treeNode), treeNode, srcNode);
            break;

        case NI_System_Math_Round:
            genConsumeOperands(treeNode->AsOp());
            GetEmitter()->emitInsBinary(INS_frintn, emitActualTypeSize(treeNode), treeNode, srcNode);
            break;

        case NI_System_Math_Max:
        {
            genConsumeOperands(treeNode->AsOp());
            GetEmitter()->emitIns_R_R_R(INS_fmax, emitActualTypeSize(treeNode), treeNode->GetRegNum(),
                                        srcNode->GetRegNum(), treeNode->gtGetOp2()->GetRegNum());
            break;
        }

        case NI_System_Math_MaxNumber:
        {
            genConsumeOperands(treeNode->AsOp());
            GetEmitter()->emitIns_R_R_R(INS_fmaxnm, emitActualTypeSize(treeNode), treeNode->GetRegNum(),
                                        srcNode->GetRegNum(), treeNode->gtGetOp2()->GetRegNum());
            break;
        }

        case NI_System_Math_Min:
        {
            genConsumeOperands(treeNode->AsOp());
            GetEmitter()->emitIns_R_R_R(INS_fmin, emitActualTypeSize(treeNode), treeNode->GetRegNum(),
                                        srcNode->GetRegNum(), treeNode->gtGetOp2()->GetRegNum());
            break;
        }

        case NI_System_Math_MinNumber:
        {
            genConsumeOperands(treeNode->AsOp());
            GetEmitter()->emitIns_R_R_R(INS_fminnm, emitActualTypeSize(treeNode), treeNode->GetRegNum(),
                                        srcNode->GetRegNum(), treeNode->gtGetOp2()->GetRegNum());
            break;
        }
#endif // TARGET_ARM64

        case NI_System_Math_Sqrt:
            genConsumeOperands(treeNode->AsOp());
            GetEmitter()->emitInsBinary(INS_SQRT, emitActualTypeSize(treeNode), treeNode, srcNode);
            break;

#if defined(FEATURE_SIMD)
            // The handling is a bit more complex so genSimdUpperSave/Restore
            // handles genConsumeOperands and genProduceReg

        case NI_SIMD_UpperRestore:
        {
            genSimdUpperRestore(treeNode);
            return;
        }

        case NI_SIMD_UpperSave:
        {
            genSimdUpperSave(treeNode);
            return;
        }
#endif // FEATURE_SIMD

        default:
            assert(!"genIntrinsic: Unsupported intrinsic");
            unreached();
    }

    genProduceReg(treeNode);
}

//---------------------------------------------------------------------
// genPutArgStk - generate code for a GT_PUTARG_STK node
//
// Arguments
//    treeNode - the GT_PUTARG_STK node
//
// Return value:
//    None
//
void CodeGen::genPutArgStk(GenTreePutArgStk* treeNode)
{
    assert(treeNode->OperIs(GT_PUTARG_STK));
    emitter* emit = GetEmitter();

    // This is the varNum for our store operations,
    // typically this is the varNum for the Outgoing arg space
    // When we are generating a tail call it will be the varNum for arg0
    unsigned varNumOut    = (unsigned)-1;
    unsigned argOffsetMax = (unsigned)-1; // Records the maximum size of this area for assert checks

    // Get argument offset to use with 'varNumOut'
    // Here we cross check that argument offset hasn't changed from lowering to codegen since
    // we are storing arg slot number in GT_PUTARG_STK node in lowering phase.
    unsigned argOffsetOut = treeNode->getArgOffset();

    // Whether to setup stk arg in incoming or out-going arg area?
    // Fast tail calls implemented as epilog+jmp = stk arg is setup in incoming arg area.
    // All other calls - stk arg is setup in out-going arg area.
    if (treeNode->putInIncomingArgArea())
    {
        varNumOut    = getFirstArgWithStackSlot();
        argOffsetMax = compiler->compArgSize;
#if FEATURE_FASTTAILCALL
        // This must be a fast tail call.
        assert(treeNode->gtCall->IsFastTailCall());

        // Since it is a fast tail call, the existence of first incoming arg is guaranteed
        // because fast tail call requires that in-coming arg area of caller is >= out-going
        // arg area required for tail call.
        LclVarDsc* varDsc = compiler->lvaGetDesc(varNumOut);
        assert(varDsc != nullptr);
#endif // FEATURE_FASTTAILCALL
    }
    else
    {
        varNumOut    = compiler->lvaOutgoingArgSpaceVar;
        argOffsetMax = compiler->lvaOutgoingArgSpaceSize;
    }

    GenTree* source = treeNode->gtGetOp1();

    if (!source->TypeIs(TYP_STRUCT)) // a normal non-Struct argument
    {
        if (varTypeIsSIMD(source->TypeGet()))
        {
            assert(!source->isContained());

            regNumber srcReg = genConsumeReg(source);
            assert((srcReg != REG_NA) && (genIsValidFloatReg(srcReg)));

            assert(compAppleArm64Abi() || treeNode->GetStackByteSize() % TARGET_POINTER_SIZE == 0);

#ifdef TARGET_ARM64
            if (treeNode->GetStackByteSize() == 12)
            {
                GetEmitter()->emitStoreSimd12ToLclOffset(varNumOut, argOffsetOut, srcReg, treeNode);
                argOffsetOut += 12;
            }
            else
#endif // TARGET_ARM64
            {
                emitAttr storeAttr = emitTypeSize(source->TypeGet());
                emit->emitIns_S_R(INS_str, storeAttr, srcReg, varNumOut, argOffsetOut);
                argOffsetOut += EA_SIZE_IN_BYTES(storeAttr);
            }
            assert(argOffsetOut <= argOffsetMax); // We can't write beyond the outgoing arg area
            return;
        }

        var_types slotType = genActualType(source);
        if (compAppleArm64Abi())
        {
            // Small typed args do not get their own full stack slots, so make
            // sure we do not overwrite adjacent arguments.
            switch (treeNode->GetStackByteSize())
            {
                case 1:
                    slotType = TYP_BYTE;
                    break;
                case 2:
                    slotType = TYP_SHORT;
                    break;
                default:
                    assert(treeNode->GetStackByteSize() >= 4);
                    break;
            }
        }

        instruction storeIns  = ins_Store(slotType);
        emitAttr    storeAttr = emitTypeSize(slotType);

        // If it is contained then source must be the integer constant zero
        if (source->isContained())
        {
#ifdef TARGET_ARM64
            assert(source->OperGet() == GT_CNS_INT);
            assert(source->AsIntConCommon()->IconValue() == 0);

            emit->emitIns_S_R(storeIns, storeAttr, REG_ZR, varNumOut, argOffsetOut);
#else  // !TARGET_ARM64
       // There is no zero register on ARM32
            unreached();
#endif // !TARGET_ARM64
        }
        else
        {
            genConsumeReg(source);
            emit->emitIns_S_R(storeIns, storeAttr, source->GetRegNum(), varNumOut, argOffsetOut);
#ifdef TARGET_ARM
            if (source->TypeIs(TYP_LONG))
            {
                // This case currently only occurs for double types that are passed as TYP_LONG;
                // actual long types would have been decomposed by now.
                assert(source->IsCopyOrReload());
                regNumber otherReg = (regNumber)source->AsCopyOrReload()->GetRegNumByIdx(1);
                assert(otherReg != REG_NA);
                argOffsetOut += EA_4BYTE;
                emit->emitIns_S_R(storeIns, storeAttr, otherReg, varNumOut, argOffsetOut);
            }
#endif // TARGET_ARM
        }
        argOffsetOut += EA_SIZE_IN_BYTES(storeAttr);
        assert(argOffsetOut <= argOffsetMax); // We can't write beyond the outgoing arg area
    }
    else // We have some kind of a struct argument
    {
        assert(source->isContained()); // We expect that this node was marked as contained in Lower

        if (source->OperGet() == GT_FIELD_LIST)
        {
            genPutArgStkFieldList(treeNode, varNumOut);
        }
        else
        {
            noway_assert(source->OperIsLocalRead() || source->OperIs(GT_BLK));

            var_types targetType = source->TypeGet();
            noway_assert(varTypeIsStruct(targetType));

            // We will copy this struct to the stack, possibly using a ldp/ldr instruction
            // in ARM64/ARM
            // Setup loReg (and hiReg) from the internal registers that we reserved in lower.
            //
            regNumber loReg = treeNode->ExtractTempReg();
#ifdef TARGET_ARM64
            regNumber hiReg = treeNode->GetSingleTempReg();
#endif // TARGET_ARM64

            GenTreeLclVarCommon* srcLclNode = nullptr;
            regNumber            addrReg    = REG_NA;
            ClassLayout*         layout     = nullptr;

            // Setup "layout", "srcLclNode" and "addrReg".
            if (source->OperIsLocalRead())
            {
                srcLclNode        = source->AsLclVarCommon();
                layout            = srcLclNode->GetLayout(compiler);
                LclVarDsc* varDsc = compiler->lvaGetDesc(srcLclNode);

                // This struct must live on the stack frame.
                assert(varDsc->lvOnFrame && !varDsc->lvRegister);
            }
            else // we must have a GT_BLK
            {
                layout  = source->AsBlk()->GetLayout();
                addrReg = genConsumeReg(source->AsBlk()->Addr());

#ifdef TARGET_ARM64
                // If addrReg equal to loReg, swap(loReg, hiReg)
                // This reduces code complexity by only supporting one addrReg overwrite case
                if (loReg == addrReg)
                {
                    loReg = hiReg;
                    hiReg = addrReg;
                }
#endif // TARGET_ARM64
            }

            unsigned srcSize = layout->GetSize();

            // If we have an HFA we can't have any GC pointers,
            // if not then the max size for the struct is 16 bytes
            if (compiler->IsHfa(layout->GetClassHandle()))
            {
                noway_assert(!layout->HasGCPtr());
            }
#ifdef TARGET_ARM64
            else
            {
                noway_assert(srcSize <= 2 * TARGET_POINTER_SIZE);
            }

            noway_assert(srcSize <= MAX_PASS_MULTIREG_BYTES);
#endif // TARGET_ARM64

            unsigned dstSize = treeNode->GetStackByteSize();

            // We can generate smaller code if store size is a multiple of TARGET_POINTER_SIZE.
            // The dst size can be rounded up to PUTARG_STK size. The src size can be rounded up
            // if it reads a local variable because reading "too much" from a local cannot fault.
            // We must also be careful to check for the arm64 apple case where arguments can be
            // passed without padding.
            //
            if ((dstSize != srcSize) && (srcLclNode != nullptr))
            {
                unsigned widenedSrcSize = roundUp(srcSize, TARGET_POINTER_SIZE);
                if (widenedSrcSize <= dstSize)
                {
                    srcSize = widenedSrcSize;
                }
            }

            assert(srcSize <= dstSize);

            int      remainingSize = srcSize;
            unsigned structOffset  = 0;
            unsigned lclOffset     = (srcLclNode != nullptr) ? srcLclNode->GetLclOffs() : 0;
            unsigned nextIndex     = 0;

#ifdef TARGET_ARM64
            // For a >= 16-byte sizes we will generate a ldp and stp instruction each loop
            //             ldp     x2, x3, [x0]
            //             stp     x2, x3, [sp, #16]

            while (remainingSize >= 2 * TARGET_POINTER_SIZE)
            {
                var_types type0 = layout->GetGCPtrType(nextIndex + 0);
                var_types type1 = layout->GetGCPtrType(nextIndex + 1);

                if (srcLclNode != nullptr)
                {
                    // Load from our local source
                    emit->emitIns_R_R_S_S(INS_ldp, emitTypeSize(type0), emitTypeSize(type1), loReg, hiReg,
                                          srcLclNode->GetLclNum(), lclOffset + structOffset);
                }
                else
                {
                    // check for case of destroying the addrRegister while we still need it
                    assert(loReg != addrReg);
                    noway_assert((remainingSize == 2 * TARGET_POINTER_SIZE) || (hiReg != addrReg));

                    // Load from our address expression source
                    emit->emitIns_R_R_R_I(INS_ldp, emitTypeSize(type0), loReg, hiReg, addrReg, structOffset,
                                          INS_OPTS_NONE, emitTypeSize(type0));
                }

                // Emit stp instruction to store the two registers into the outgoing argument area
                emit->emitIns_S_S_R_R(INS_stp, emitTypeSize(type0), emitTypeSize(type1), loReg, hiReg, varNumOut,
                                      argOffsetOut);
                argOffsetOut += (2 * TARGET_POINTER_SIZE); // We stored 16-bytes of the struct
                assert(argOffsetOut <= argOffsetMax);      // We can't write beyond the outgoing arg area

                remainingSize -= (2 * TARGET_POINTER_SIZE); // We loaded 16-bytes of the struct
                structOffset += (2 * TARGET_POINTER_SIZE);
                nextIndex += 2;
            }
#else  // TARGET_ARM
       // For a >= 4 byte sizes we will generate a ldr and str instruction each loop
       //             ldr     r2, [r0]
       //             str     r2, [sp, #16]
            while (remainingSize >= TARGET_POINTER_SIZE)
            {
                var_types type = layout->GetGCPtrType(nextIndex);

                if (srcLclNode != nullptr)
                {
                    // Load from our local source
                    emit->emitIns_R_S(INS_ldr, emitTypeSize(type), loReg, srcLclNode->GetLclNum(),
                                      lclOffset + structOffset);
                }
                else
                {
                    // check for case of destroying the addrRegister while we still need it
                    assert(loReg != addrReg || remainingSize == TARGET_POINTER_SIZE);

                    // Load from our address expression source
                    emit->emitIns_R_R_I(INS_ldr, emitTypeSize(type), loReg, addrReg, structOffset);
                }

                // Emit str instruction to store the register into the outgoing argument area
                emit->emitIns_S_R(INS_str, emitTypeSize(type), loReg, varNumOut, argOffsetOut);
                argOffsetOut += TARGET_POINTER_SIZE;  // We stored 4-bytes of the struct
                assert(argOffsetOut <= argOffsetMax); // We can't write beyond the outgoing arg area

                remainingSize -= TARGET_POINTER_SIZE; // We loaded 4-bytes of the struct
                structOffset += TARGET_POINTER_SIZE;
                nextIndex += 1;
            }
#endif // TARGET_ARM

            // For a 12-byte size we will generate two load instructions
            //             ldr     x2, [x0]
            //             ldr     w3, [x0, #8]
            //             str     x2, [sp, #16]
            //             str     w3, [sp, #24]

            while (remainingSize > 0)
            {
                nextIndex = structOffset / TARGET_POINTER_SIZE;

                var_types type;
                if (remainingSize >= TARGET_POINTER_SIZE)
                {
                    type = layout->GetGCPtrType(nextIndex);
                }
                else // (remainingSize < TARGET_POINTER_SIZE)
                {
                    // the left over size is smaller than a pointer and thus can never be a GC type
                    assert(!layout->IsGCPtr(nextIndex));

                    if (remainingSize >= 4)
                    {
                        type = TYP_INT;
                    }
                    else if (remainingSize >= 2)
                    {
                        type = TYP_USHORT;
                    }
                    else
                    {
                        assert(remainingSize == 1);
                        type = TYP_UBYTE;
                    }
                }

                const emitAttr attr     = emitActualTypeSize(type);
                const unsigned moveSize = genTypeSize(type);

                remainingSize -= moveSize;

                instruction loadIns = ins_Load(type);
                if (srcLclNode != nullptr)
                {
                    // Load from our local source
                    emit->emitIns_R_S(loadIns, attr, loReg, srcLclNode->GetLclNum(), lclOffset + structOffset);
                }
                else
                {
                    assert(loReg != addrReg);
                    // Load from our address expression source
                    emit->emitIns_R_R_I(loadIns, attr, loReg, addrReg, structOffset);
                }

                // Emit a store instruction to store the register into the outgoing argument area
                instruction storeIns = ins_Store(type);
                emit->emitIns_S_R(storeIns, attr, loReg, varNumOut, argOffsetOut);
                argOffsetOut += moveSize;
                assert(argOffsetOut <= argOffsetMax); // We can't write beyond the outgoing arg area

                structOffset += moveSize;
            }
        }
    }
}

//---------------------------------------------------------------------
// genPutArgReg - generate code for a GT_PUTARG_REG node
//
// Arguments
//    tree - the GT_PUTARG_REG node
//
// Return value:
//    None
//
void CodeGen::genPutArgReg(GenTreeOp* tree)
{
    assert(tree->OperIs(GT_PUTARG_REG));

    var_types targetType = tree->TypeGet();
    regNumber targetReg  = tree->GetRegNum();

    assert(targetType != TYP_STRUCT);

    GenTree* op1 = tree->gtOp1;
    genConsumeReg(op1);

    // If child node is not already in the register we need, move it
    inst_Mov(targetType, targetReg, op1->GetRegNum(), /* canSkip */ true);

    genProduceReg(tree);
}

//---------------------------------------------------------------------
// genPutArgSplit - generate code for a GT_PUTARG_SPLIT node
//
// Arguments
//    tree - the GT_PUTARG_SPLIT node
//
// Return value:
//    None
//
void CodeGen::genPutArgSplit(GenTreePutArgSplit* treeNode)
{
    assert(treeNode->OperIs(GT_PUTARG_SPLIT));

    GenTree* source       = treeNode->gtOp1;
    emitter* emit         = GetEmitter();
    unsigned varNumOut    = compiler->lvaOutgoingArgSpaceVar;
    unsigned argOffsetMax = compiler->lvaOutgoingArgSpaceSize;

    if (source->OperGet() == GT_FIELD_LIST)
    {
        // Evaluate each of the GT_FIELD_LIST items into their register
        // and store their register into the outgoing argument area
        unsigned regIndex         = 0;
        unsigned firstOnStackOffs = UINT_MAX;

        for (GenTreeFieldList::Use& use : source->AsFieldList()->Uses())
        {
            GenTree*  nextArgNode = use.GetNode();
            regNumber fieldReg    = nextArgNode->GetRegNum();
            genConsumeReg(nextArgNode);

            if (regIndex >= treeNode->gtNumRegs)
            {
                if (firstOnStackOffs == UINT_MAX)
                {
                    firstOnStackOffs = use.GetOffset();
                }

                var_types type   = use.GetType();
                unsigned  offset = treeNode->getArgOffset() + use.GetOffset() - firstOnStackOffs;
                // We can't write beyond the outgoing arg area
                assert((offset + genTypeSize(type)) <= argOffsetMax);

                // Emit store instructions to store the registers produced by the GT_FIELD_LIST into the outgoing
                // argument area
                emit->emitIns_S_R(ins_Store(type), emitActualTypeSize(type), fieldReg, varNumOut, offset);
            }
            else
            {
                var_types type   = treeNode->GetRegType(regIndex);
                regNumber argReg = treeNode->GetRegNumByIdx(regIndex);
#ifdef TARGET_ARM
                if (type == TYP_LONG)
                {
                    // We should only see long fields for DOUBLEs passed in 2 integer registers, via bitcast.
                    // All other LONGs should have been decomposed.
                    // Handle the first INT, and then handle the 2nd below.
                    assert(nextArgNode->OperIs(GT_BITCAST));
                    type = TYP_INT;
                    inst_Mov(type, argReg, fieldReg, /* canSkip */ true);

                    // Now set up the next register for the 2nd INT
                    argReg = REG_NEXT(argReg);
                    regIndex++;
                    assert(argReg == treeNode->GetRegNumByIdx(regIndex));
                    fieldReg = nextArgNode->AsMultiRegOp()->GetRegNumByIdx(1);
                }
#endif // TARGET_ARM

                // If child node is not already in the register we need, move it
                inst_Mov(type, argReg, fieldReg, /* canSkip */ true);

                regIndex++;
            }
        }
    }
    else
    {
        var_types targetType = source->TypeGet();
        assert(source->isContained() && varTypeIsStruct(targetType));

        // We need a register to store intermediate values that we are loading
        // from the source into. We can usually use one of the target registers
        // that will be overridden anyway. The exception is when the source is
        // in a register and that register is the unique target register we are
        // placing. LSRA will always allocate an internal register when there
        // is just one target register to handle this situation.
        //
        int          firstRegToPlace;
        regNumber    valueReg     = REG_NA;
        unsigned     srcLclNum    = BAD_VAR_NUM;
        unsigned     srcLclOffset = 0;
        regNumber    addrReg      = REG_NA;
        var_types    addrType     = TYP_UNDEF;
        ClassLayout* layout       = nullptr;

        if (source->OperIsLocalRead())
        {
            srcLclNum         = source->AsLclVarCommon()->GetLclNum();
            srcLclOffset      = source->AsLclVarCommon()->GetLclOffs();
            layout            = source->AsLclVarCommon()->GetLayout(compiler);
            LclVarDsc* varDsc = compiler->lvaGetDesc(srcLclNum);

            // This struct must live on the stack frame.
            assert(varDsc->lvOnFrame && !varDsc->lvRegister);

            // No possible conflicts, just use the first register as the value register.
            firstRegToPlace = 0;
            valueReg        = treeNode->GetRegNumByIdx(0);
        }
        else // we must have a GT_BLK
        {
            layout   = source->AsBlk()->GetLayout();
            addrReg  = genConsumeReg(source->AsBlk()->Addr());
            addrType = source->AsBlk()->Addr()->TypeGet();

            regNumber allocatedValueReg = REG_NA;
            if (treeNode->gtNumRegs == 1)
            {
                allocatedValueReg = treeNode->ExtractTempReg();
            }

            // Pick a register to store intermediate values in for the to-stack
            // copy. It must not conflict with addrReg. We try to prefer an
            // argument register since those can always use thumb encoding.
            valueReg = treeNode->GetRegNumByIdx(0);
            if (valueReg == addrReg)
            {
                if (treeNode->gtNumRegs == 1)
                {
                    valueReg = allocatedValueReg;
                }
                else
                {
                    // Prefer argument register that can always use thumb encoding.
                    valueReg = treeNode->GetRegNumByIdx(1);
                }
            }

            // Find first register to place. If we are placing addrReg, then
            // make sure we place it last to avoid clobbering its value.
            //
            // The loop below will start at firstRegToPlace and place
            // treeNode->gtNumRegs registers in order, with wraparound. For
            // example, if the registers to place are r0, r1, r2=addrReg, r3
            // then we will set firstRegToPlace = 3 (r3) and the loop below
            // will place r3, r0, r1, r2. The last placement will clobber
            // addrReg.
            firstRegToPlace = 0;
            for (unsigned i = 0; i < treeNode->gtNumRegs; i++)
            {
                if (treeNode->GetRegNumByIdx(i) == addrReg)
                {
                    firstRegToPlace = i + 1;
                    break;
                }
            }
        }

        // Put on stack first
        unsigned structOffset  = treeNode->gtNumRegs * TARGET_POINTER_SIZE;
        unsigned remainingSize = layout->GetSize() - structOffset;
        unsigned argOffsetOut  = treeNode->getArgOffset();

        assert((remainingSize > 0) && (roundUp(remainingSize, TARGET_POINTER_SIZE) == treeNode->GetStackByteSize()));
        while (remainingSize > 0)
        {
            var_types type;
            if (remainingSize >= TARGET_POINTER_SIZE)
            {
                type = layout->GetGCPtrType(structOffset / TARGET_POINTER_SIZE);
            }
            else if (remainingSize >= 4)
            {
                type = TYP_INT;
            }
            else if (remainingSize >= 2)
            {
                type = TYP_USHORT;
            }
            else
            {
                assert(remainingSize == 1);
                type = TYP_UBYTE;
            }

            emitAttr attr     = emitActualTypeSize(type);
            unsigned moveSize = genTypeSize(type);

            instruction loadIns = ins_Load(type);
            if (srcLclNum != BAD_VAR_NUM)
            {
                // Load from our local source
                emit->emitIns_R_S(loadIns, attr, valueReg, srcLclNum, srcLclOffset + structOffset);
            }
            else
            {
                assert(valueReg != addrReg);

                // Load from our address expression source
                emit->emitIns_R_R_I(loadIns, attr, valueReg, addrReg, structOffset);
            }

            // Emit the instruction to store the register into the outgoing argument area
            emit->emitIns_S_R(ins_Store(type), attr, valueReg, varNumOut, argOffsetOut);
            argOffsetOut += moveSize;
            assert(argOffsetOut <= argOffsetMax);

            remainingSize -= moveSize;
            structOffset += moveSize;
        }

        // Place registers starting from firstRegToPlace. It should ensure we
        // place addrReg last (if we place it at all).
        structOffset         = static_cast<unsigned>(firstRegToPlace) * TARGET_POINTER_SIZE;
        unsigned curRegIndex = firstRegToPlace;

        for (unsigned regsPlaced = 0; regsPlaced < treeNode->gtNumRegs; regsPlaced++)
        {
            if (curRegIndex == treeNode->gtNumRegs)
            {
                curRegIndex  = 0;
                structOffset = 0;
            }

            regNumber targetReg = treeNode->GetRegNumByIdx(curRegIndex);
            var_types type      = treeNode->GetRegType(curRegIndex);

            if (srcLclNum != BAD_VAR_NUM)
            {
                // Load from our local source
                emit->emitIns_R_S(INS_ldr, emitTypeSize(type), targetReg, srcLclNum, srcLclOffset + structOffset);
            }
            else
            {
                assert((addrReg != targetReg) || (regsPlaced == treeNode->gtNumRegs - 1));

                // Load from our address expression source
                emit->emitIns_R_R_I(INS_ldr, emitTypeSize(type), targetReg, addrReg, structOffset);
            }

            curRegIndex++;
            structOffset += TARGET_POINTER_SIZE;
        }
    }
    genProduceReg(treeNode);
}

#ifdef FEATURE_SIMD
//----------------------------------------------------------------------------------
// genMultiRegStoreToSIMDLocal: store multi-reg value to a single-reg SIMD local
//
// Arguments:
//    lclNode  -  GentreeLclVar of GT_STORE_LCL_VAR
//
// Return Value:
//    None
//
void CodeGen::genMultiRegStoreToSIMDLocal(GenTreeLclVar* lclNode)
{
    regNumber dst       = lclNode->GetRegNum();
    GenTree*  op1       = lclNode->gtGetOp1();
    GenTree*  actualOp1 = op1->gtSkipReloadOrCopy();
    unsigned  regCount  = actualOp1->GetMultiRegCount(compiler);
    assert(op1->IsMultiRegNode());
    genConsumeRegs(op1);

    // Treat dst register as a homogeneous vector with element size equal to the src size
    // Insert pieces in reverse order
    for (int i = regCount - 1; i >= 0; --i)
    {
        var_types type = op1->gtSkipReloadOrCopy()->GetRegTypeByIndex(i);
        regNumber reg  = actualOp1->GetRegByIndex(i);
        if (op1->IsCopyOrReload())
        {
            // GT_COPY/GT_RELOAD will have valid reg for those positions
            // that need to be copied or reloaded.
            regNumber reloadReg = op1->AsCopyOrReload()->GetRegNumByIdx(i);
            if (reloadReg != REG_NA)
            {
                reg = reloadReg;
            }
        }

        assert(reg != REG_NA);
        if (varTypeIsFloating(type))
        {
            // If the register piece was passed in a floating point register
            // Use a vector mov element instruction
            // src is not a vector, so it is in the first element reg[0]
            // mov dst[i], reg[0]
            // This effectively moves from `reg[0]` to `dst[i]`, leaving other dst bits unchanged till further
            // iterations
            // For the case where reg == dst, if we iterate so that we write dst[0] last, we eliminate the need for
            // a temporary
            GetEmitter()->emitIns_R_R_I_I(INS_mov, emitTypeSize(type), dst, reg, i, 0);
        }
        else
        {
            // If the register piece was passed in an integer register
            // Use a vector mov from general purpose register instruction
            // mov dst[i], reg
            // This effectively moves from `reg` to `dst[i]`
            GetEmitter()->emitIns_R_R_I(INS_mov, emitTypeSize(type), dst, reg, i);
        }
    }

    genProduceReg(lclNode);
}
#endif // FEATURE_SIMD

//------------------------------------------------------------------------
// genRangeCheck: generate code for GT_BOUNDS_CHECK node.
//
void CodeGen::genRangeCheck(GenTree* oper)
{
    noway_assert(oper->OperIs(GT_BOUNDS_CHECK));
    GenTreeBoundsChk* bndsChk = oper->AsBoundsChk();

    GenTree* arrLen    = bndsChk->GetArrayLength();
    GenTree* arrIndex  = bndsChk->GetIndex();
    GenTree* arrRef    = nullptr;
    int      lenOffset = 0;

    GenTree*     src1;
    GenTree*     src2;
    emitJumpKind jmpKind;

    genConsumeRegs(arrIndex);
    genConsumeRegs(arrLen);

    if (arrIndex->isContainedIntOrIImmed())
    {
        // To encode using a cmp immediate, we place the
        //  constant operand in the second position
        src1    = arrLen;
        src2    = arrIndex;
        jmpKind = EJ_ls;
    }
    else
    {
        src1    = arrIndex;
        src2    = arrLen;
        jmpKind = EJ_hs;
    }

    var_types bndsChkType = genActualType(src2->TypeGet());
#if DEBUG
    // Bounds checks can only be 32 or 64 bit sized comparisons.
    assert(bndsChkType == TYP_INT || bndsChkType == TYP_LONG);

    // The type of the bounds check should always wide enough to compare against the index.
    assert(emitTypeSize(bndsChkType) >= emitActualTypeSize(src1->TypeGet()));
#endif // DEBUG

    GetEmitter()->emitInsBinary(INS_cmp, emitActualTypeSize(bndsChkType), src1, src2);
    genJumpToThrowHlpBlk(jmpKind, bndsChk->gtThrowKind, bndsChk->gtIndRngFailBB);
}

//---------------------------------------------------------------------
// genCodeForPhysReg - generate code for a GT_PHYSREG node
//
// Arguments
//    tree - the GT_PHYSREG node
//
// Return value:
//    None
//
void CodeGen::genCodeForPhysReg(GenTreePhysReg* tree)
{
    assert(tree->OperIs(GT_PHYSREG));

    var_types targetType = tree->TypeGet();
    regNumber targetReg  = tree->GetRegNum();

    inst_Mov(targetType, targetReg, tree->gtSrcReg, /* canSkip */ true);
    genTransferRegGCState(targetReg, tree->gtSrcReg);

    genProduceReg(tree);
}

//---------------------------------------------------------------------
// genCodeForNullCheck - generate code for a GT_NULLCHECK node
//
// Arguments
//    tree - the GT_NULLCHECK node
//
// Return value:
//    None
//
void CodeGen::genCodeForNullCheck(GenTreeIndir* tree)
{
#ifdef TARGET_ARM
    assert(!"GT_NULLCHECK isn't supported for Arm32; use GT_IND.");
#else
    assert(tree->OperIs(GT_NULLCHECK));
    GenTree* op1 = tree->gtOp1;

    genConsumeRegs(op1);
    regNumber targetReg = REG_ZR;

    GetEmitter()->emitInsLoadStoreOp(ins_Load(tree->TypeGet()), emitActualTypeSize(tree), targetReg, tree);
#endif
}

//------------------------------------------------------------------------
// genCodeForShift: Generates the code sequence for a GenTree node that
// represents a bit shift or rotate operation (<<, >>, >>>, rol, ror).
//
// Arguments:
//    tree - the bit shift node (that specifies the type of bit shift to perform).
//
// Assumptions:
//    a) All GenTrees are register allocated.
//
void CodeGen::genCodeForShift(GenTree* tree)
{
    var_types   targetType = tree->TypeGet();
    genTreeOps  oper       = tree->OperGet();
    instruction ins        = genGetInsForOper(oper, targetType);
    emitAttr    size       = emitActualTypeSize(tree);
    regNumber   dstReg     = tree->GetRegNum();

    assert(dstReg != REG_NA);

    genConsumeOperands(tree->AsOp());

    GenTree* operand = tree->gtGetOp1();
    GenTree* shiftBy = tree->gtGetOp2();
    if (!shiftBy->IsCnsIntOrI())
    {
        GetEmitter()->emitIns_R_R_R(ins, size, dstReg, operand->GetRegNum(), shiftBy->GetRegNum());
    }
    else
    {
        unsigned immWidth   = emitter::getBitWidth(size); // For ARM64, immWidth will be set to 32 or 64
        unsigned shiftByImm = (unsigned)shiftBy->AsIntCon()->gtIconVal & (immWidth - 1);
        GetEmitter()->emitIns_R_R_I(ins, size, dstReg, operand->GetRegNum(), shiftByImm);
    }

    genProduceReg(tree);
}

//------------------------------------------------------------------------
// genCodeForLclAddr: Generates the code for GT_LCL_ADDR.
//
// Arguments:
//    lclAddrNode - the node.
//
void CodeGen::genCodeForLclAddr(GenTreeLclFld* lclAddrNode)
{
    assert(lclAddrNode->OperIs(GT_LCL_ADDR));

    var_types targetType = lclAddrNode->TypeGet();
    emitAttr  size       = emitTypeSize(targetType);
    regNumber targetReg  = lclAddrNode->GetRegNum();

    // Address of a local var.
    noway_assert((targetType == TYP_BYREF) || (targetType == TYP_I_IMPL));

    GetEmitter()->emitIns_R_S(INS_lea, size, targetReg, lclAddrNode->GetLclNum(), lclAddrNode->GetLclOffs());

    genProduceReg(lclAddrNode);
}

//------------------------------------------------------------------------
// genCodeForLclFld: Produce code for a GT_LCL_FLD node.
//
// Arguments:
//    tree - the GT_LCL_FLD node
//
void CodeGen::genCodeForLclFld(GenTreeLclFld* tree)
{
    assert(tree->OperIs(GT_LCL_FLD));

    var_types targetType = tree->TypeGet();
    regNumber targetReg  = tree->GetRegNum();
    emitter*  emit       = GetEmitter();

    NYI_IF(targetType == TYP_STRUCT, "GT_LCL_FLD: struct load local field not supported");
    assert(targetReg != REG_NA);

    unsigned offs   = tree->GetLclOffs();
    unsigned varNum = tree->GetLclNum();
    assert(varNum < compiler->lvaCount);

#ifdef TARGET_ARM
    if (tree->IsOffsetMisaligned())
    {
        // Arm supports unaligned access only for integer types,
        // load the floating data as 1 or 2 integer registers and convert them to float.
        regNumber addr = tree->ExtractTempReg();
        emit->emitIns_R_S(INS_lea, EA_PTRSIZE, addr, varNum, offs);

        if (targetType == TYP_FLOAT)
        {
            regNumber floatAsInt = tree->GetSingleTempReg();
            emit->emitIns_R_R(INS_ldr, EA_4BYTE, floatAsInt, addr);
            emit->emitIns_Mov(INS_vmov_i2f, EA_4BYTE, targetReg, floatAsInt, /* canSkip */ false);
        }
        else
        {
            regNumber halfdoubleAsInt1 = tree->ExtractTempReg();
            regNumber halfdoubleAsInt2 = tree->GetSingleTempReg();
            emit->emitIns_R_R_I(INS_ldr, EA_4BYTE, halfdoubleAsInt1, addr, 0);
            emit->emitIns_R_R_I(INS_ldr, EA_4BYTE, halfdoubleAsInt2, addr, 4);
            emit->emitIns_R_R_R(INS_vmov_i2d, EA_8BYTE, targetReg, halfdoubleAsInt1, halfdoubleAsInt2);
        }
    }
    else
#endif // TARGET_ARM
    {
        emitAttr    attr = emitActualTypeSize(targetType);
        instruction ins  = ins_Load(targetType);
        emit->emitIns_R_S(ins, attr, targetReg, varNum, offs);
    }

    genProduceReg(tree);
}

//------------------------------------------------------------------------
// genCodeForIndexAddr: Produce code for a GT_INDEX_ADDR node.
//
// Arguments:
//    tree - the GT_INDEX_ADDR node
//
void CodeGen::genCodeForIndexAddr(GenTreeIndexAddr* node)
{
    GenTree* const base  = node->Arr();
    GenTree* const index = node->Index();

    genConsumeReg(base);
    genConsumeReg(index);

    // NOTE: `genConsumeReg` marks the consumed register as not a GC pointer, as it assumes that the input registers
    // die at the first instruction generated by the node. This is not the case for `INDEX_ADDR`, however, as the
    // base register is multiply-used. As such, we need to mark the base register as containing a GC pointer until
    // we are finished generating the code for this node.

    gcInfo.gcMarkRegPtrVal(base->GetRegNum(), base->TypeGet());
    assert(!varTypeIsGC(index->TypeGet()));

    // The index is never contained, even if it is a constant.
    assert(index->isUsedFromReg());

    const regNumber tmpReg = node->ExtractTempReg();

    regNumber indexReg = index->GetRegNum();

    // Generate the bounds check if necessary.
    if (node->IsBoundsChecked())
    {
        GetEmitter()->emitIns_R_R_I(INS_ldr, EA_4BYTE, tmpReg, base->GetRegNum(), node->gtLenOffset);
        GetEmitter()->emitIns_R_R(INS_cmp, emitActualTypeSize(index->TypeGet()), indexReg, tmpReg);
        genJumpToThrowHlpBlk(EJ_hs, SCK_RNGCHK_FAIL, node->gtIndRngFailBB);
    }

    // Can we use a ScaledAdd instruction?
    //
    if (isPow2(node->gtElemSize) && (node->gtElemSize <= 32768))
    {
        DWORD scale;
        BitScanForward(&scale, node->gtElemSize);

#ifdef TARGET_ARM64
        if (!index->TypeIs(TYP_I_IMPL))
        {
            if (scale <= 4)
            {
                // target = base + index<<scale
                GetEmitter()->emitIns_R_R_R_I(INS_add, emitActualTypeSize(node), node->GetRegNum(), base->GetRegNum(),
                                              indexReg, scale, INS_OPTS_UXTW);
            }
            else
            {
                GetEmitter()->emitIns_Mov(INS_mov, EA_4BYTE, tmpReg, indexReg, /* canSkip */ false);
                indexReg      = tmpReg;
                emitter* emit = GetEmitter();
                genScaledAdd(emitActualTypeSize(node), node->GetRegNum(), base->GetRegNum(), indexReg, scale);
            }
        }
        else
#endif // TARGET_ARM64
        {
            // dest = base + index * scale
            genScaledAdd(emitActualTypeSize(node), node->GetRegNum(), base->GetRegNum(), indexReg, scale);
        }
    }
    else // we have to load the element size and use a MADD (multiply-add) instruction
    {
#ifdef TARGET_ARM64
        if (!index->TypeIs(TYP_I_IMPL))
        {
            const regNumber tmpReg2 = node->ExtractTempReg();
            GetEmitter()->emitIns_Mov(INS_mov, EA_4BYTE, tmpReg2, indexReg, /* canSkip */ false);
            indexReg = tmpReg2;
        }
#endif // TARGET_ARM64

        // tmpReg = element size
        instGen_Set_Reg_To_Imm(EA_4BYTE, tmpReg, (ssize_t)node->gtElemSize);

        // dest = index * tmpReg + base
        GetEmitter()->emitIns_R_R_R_R(INS_MULADD, emitActualTypeSize(node), node->GetRegNum(), indexReg, tmpReg,
                                      base->GetRegNum());
    }

    // dest = dest + elemOffs
    GetEmitter()->emitIns_R_R_I(INS_add, emitActualTypeSize(node), node->GetRegNum(), node->GetRegNum(),
                                node->gtElemOffset);

    gcInfo.gcMarkRegSetNpt(base->gtGetRegMask());

    genProduceReg(node);
}

//------------------------------------------------------------------------
// genGetVolatileLdStIns: Determine the most efficient instruction to perform a
//    volatile load or store and whether an explicit barrier is required or not.
//
// Arguments:
//    currentIns   - the current instruction to perform load/store
//    targetReg    - the target register
//    indir        - the indirection node representing the volatile load/store
//    needsBarrier - OUT parameter. Set to true if an explicit memory barrier is required.
//
// Return Value:
//    instruction to perform the volatile load/store with.
//
instruction CodeGen::genGetVolatileLdStIns(instruction   currentIns,
                                           regNumber     targetReg,
                                           GenTreeIndir* indir,
                                           bool*         needsBarrier)
{
    assert(indir->IsVolatile());

    if (!genIsValidIntReg(targetReg))
    {
        // We don't have special instructions to perform volatile loads/stores for non-integer registers.
        *needsBarrier = true;
        return currentIns;
    }

    assert(!varTypeIsFloating(indir));
    assert(!varTypeIsSIMD(indir));

#ifdef TARGET_ARM64
    *needsBarrier = false;

    if (indir->IsUnaligned() && (currentIns != INS_ldrb) && (currentIns != INS_strb))
    {
        // We have to use a normal load/store + explicit memory barrier
        // to avoid unaligned access exceptions.
        *needsBarrier = true;
        return currentIns;
    }

    const bool addrIsInReg = indir->Addr()->isUsedFromReg();

    // With RCPC2 (arm64 v8.4+) we can work with simple addressing modes like [reg + simm9]
    const bool shouldUseRcpc2 = compiler->compOpportunisticallyDependsOn(InstructionSet_Rcpc2) && !addrIsInReg &&
                                indir->Addr()->OperIs(GT_LEA) && !indir->HasIndex() && (indir->Scale() == 1) &&
                                emitter::emitIns_valid_imm_for_unscaled_ldst_offset(indir->Offset());

    if (shouldUseRcpc2)
    {
        assert(!addrIsInReg);
        switch (currentIns)
        {
                // Loads

            case INS_ldrb:
                return INS_ldapurb;

            case INS_ldrh:
                return INS_ldapurh;

            case INS_ldr:
                return INS_ldapur;

                // Stores

            case INS_strb:
                return INS_stlurb;

            case INS_strh:
                return INS_stlurh;

            case INS_str:
                return INS_stlur;

            default:
                *needsBarrier = true;
                return currentIns;
        }
    }

    // Only RCPC2 (arm64 v8.4+) allows us to deal with contained addresses.
    // In other cases we'll have to emit a normal load/store + explicit memory barrier.
    // It means that lower should generally avoid generating contained addresses for volatile loads/stores
    // so we can use cheaper instructions.
    if (!addrIsInReg)
    {
        *needsBarrier = true;
        return currentIns;
    }

    // RCPC1 (arm64 v8.3+) offers a bit more relaxed memory ordering than ldar. Which is sufficient for
    // .NET memory model's requirements, see https://github.com/dotnet/runtime/issues/67374
    const bool hasRcpc1 = compiler->compOpportunisticallyDependsOn(InstructionSet_Rcpc);
    switch (currentIns)
    {
            // Loads

        case INS_ldrb:
            return hasRcpc1 ? INS_ldaprb : INS_ldarb;

        case INS_ldrh:
            return hasRcpc1 ? INS_ldaprh : INS_ldarh;

        case INS_ldr:
            return hasRcpc1 ? INS_ldapr : INS_ldar;

            // Stores

        case INS_strb:
            return INS_stlrb;

        case INS_strh:
            return INS_stlrh;

        case INS_str:
            return INS_stlr;

        default:
            *needsBarrier = true;
            return currentIns;
    }
#else  // TARGET_ARM64
    *needsBarrier = true;
    return currentIns;
#endif // !TARGET_ARM64
}

//------------------------------------------------------------------------
// genCodeForIndir: Produce code for a GT_IND node.
//
// Arguments:
//    tree - the GT_IND node
//
void CodeGen::genCodeForIndir(GenTreeIndir* tree)
{
    assert(tree->OperIs(GT_IND));

#ifdef FEATURE_SIMD
    // Handling of Vector3 type values loaded through indirection.
    if (tree->TypeGet() == TYP_SIMD12)
    {
        genLoadIndTypeSimd12(tree);
        return;
    }
#endif // FEATURE_SIMD

    var_types   type      = tree->TypeGet();
    instruction ins       = ins_Load(type);
    regNumber   targetReg = tree->GetRegNum();

    genConsumeAddress(tree->Addr());

    bool emitBarrier = false;

    if (tree->IsVolatile())
    {
        ins = genGetVolatileLdStIns(ins, targetReg, tree, &emitBarrier);
    }

    GetEmitter()->emitInsLoadStoreOp(ins, emitActualTypeSize(type), targetReg, tree);

    if (emitBarrier)
    {
        // when INS_ldar* could not be used for a volatile load,
        // we use an ordinary load followed by a load barrier.
        instGen_MemoryBarrier(BARRIER_LOAD_ONLY);
    }

    genProduceReg(tree);
}

#ifdef TARGET_ARM64

// The following classes
//   - InitBlockUnrollHelper
//   - CopyBlockUnrollHelper
// encapsulate algorithms that produce instruction sequences for inlined equivalents of memset() and memcpy() functions.
//
// Each class has a private template function that accepts an "InstructionStream" as a template class argument:
//   - InitBlockUnrollHelper::UnrollInitBlock<InstructionStream>(startDstOffset, byteCount, initValue)
//   - CopyBlockUnrollHelper::UnrollCopyBlock<InstructionStream>(startSrcOffset, startDstOffset, byteCount)
//
// The design goal is to separate optimization approaches implemented by the algorithms
// from the target platform specific details.
//
// InstructionStream is a "stream" of load/store instructions (i.e. ldr/ldp/str/stp) that represents an instruction
// sequence that will initialize a memory region with some value or copy values from one memory region to another.
//
// As far as UnrollInitBlock and UnrollCopyBlock concerned, InstructionStream implements the following class member
// functions:
//   - LoadPairRegs(offset, regSizeBytes)
//   - StorePairRegs(offset, regSizeBytes)
//   - LoadReg(offset, regSizeBytes)
//   - StoreReg(offset, regSizeBytes)
//
// There are three implementations of InstructionStream:
//   - CountingStream that counts how many instructions were pushed out of the stream
//   - VerifyingStream that validates that all the instructions in the stream are encodable on Arm64
//   - ProducingStream that maps the function to corresponding emitter functions
//
// The idea behind the design is that decision regarding what instruction sequence to emit
// (scalar instructions vs. SIMD instructions) is made by execution an algorithm producing an instruction sequence
// while counting the number of produced instructions and verifying that all the instructions are encodable.
//
// For example, using SIMD instructions might produce a shorter sequence but require "spilling" a value of a starting
// address
// to an integer register (due to stricter offset alignment rules for 16-byte wide SIMD instructions).
// This the CodeGen can take this fact into account before emitting an instruction sequence.
//
// Alternative design might have had VerifyingStream and ProducingStream fused into one class
// that would allow to undo an instruction if the sequence is not fully encodable.

class CountingStream
{
public:
    CountingStream()
    {
        instrCount = 0;
    }

    void LoadPairRegs(int offset, unsigned regSizeBytes)
    {
        instrCount++;
    }

    void StorePairRegs(int offset, unsigned regSizeBytes)
    {
        instrCount++;
    }

    void LoadReg(int offset, unsigned regSizeBytes)
    {
        instrCount++;
    }

    void StoreReg(int offset, unsigned regSizeBytes)
    {
        instrCount++;
    }

    unsigned InstructionCount() const
    {
        return instrCount;
    }

private:
    unsigned instrCount;
};

class VerifyingStream
{
public:
    VerifyingStream()
    {
        canEncodeAllLoads  = true;
        canEncodeAllStores = true;
    }

    void LoadPairRegs(int offset, unsigned regSizeBytes)
    {
        canEncodeAllLoads = canEncodeAllLoads && emitter::canEncodeLoadOrStorePairOffset(offset, EA_SIZE(regSizeBytes));
    }

    void StorePairRegs(int offset, unsigned regSizeBytes)
    {
        canEncodeAllStores =
            canEncodeAllStores && emitter::canEncodeLoadOrStorePairOffset(offset, EA_SIZE(regSizeBytes));
    }

    void LoadReg(int offset, unsigned regSizeBytes)
    {
        canEncodeAllLoads =
            canEncodeAllLoads && emitter::emitIns_valid_imm_for_ldst_offset(offset, EA_SIZE(regSizeBytes));
    }

    void StoreReg(int offset, unsigned regSizeBytes)
    {
        canEncodeAllStores =
            canEncodeAllStores && emitter::emitIns_valid_imm_for_ldst_offset(offset, EA_SIZE(regSizeBytes));
    }

    bool CanEncodeAllLoads() const
    {
        return canEncodeAllLoads;
    }

    bool CanEncodeAllStores() const
    {
        return canEncodeAllStores;
    }

private:
    bool canEncodeAllLoads;
    bool canEncodeAllStores;
};

class ProducingStreamBaseInstrs
{
public:
    ProducingStreamBaseInstrs(regNumber intReg1, regNumber intReg2, regNumber addrReg, emitter* emitter)
        : intReg1(intReg1)
        , intReg2(intReg2)
        , addrReg(addrReg)
        , emitter(emitter)
    {
    }

    void LoadPairRegs(int offset, unsigned regSizeBytes)
    {
        assert(regSizeBytes == 8);

        emitter->emitIns_R_R_R_I(INS_ldp, EA_SIZE(regSizeBytes), intReg1, intReg2, addrReg, offset);
    }

    void StorePairRegs(int offset, unsigned regSizeBytes)
    {
        assert(regSizeBytes == 8);

        emitter->emitIns_R_R_R_I(INS_stp, EA_SIZE(regSizeBytes), intReg1, intReg2, addrReg, offset);
    }

    void LoadReg(int offset, unsigned regSizeBytes)
    {
        instruction ins = INS_ldr;

        if (regSizeBytes == 1)
        {
            ins = INS_ldrb;
        }
        else if (regSizeBytes == 2)
        {
            ins = INS_ldrh;
        }

        emitter->emitIns_R_R_I(ins, EA_SIZE(regSizeBytes), intReg1, addrReg, offset);
    }

    void StoreReg(int offset, unsigned regSizeBytes)
    {
        instruction ins = INS_str;

        if (regSizeBytes == 1)
        {
            ins = INS_strb;
        }
        else if (regSizeBytes == 2)
        {
            ins = INS_strh;
        }

        emitter->emitIns_R_R_I(ins, EA_SIZE(regSizeBytes), intReg1, addrReg, offset);
    }

private:
    const regNumber intReg1;
    const regNumber intReg2;
    const regNumber addrReg;
    emitter* const  emitter;
};

class ProducingStream
{
public:
    ProducingStream(regNumber intReg1, regNumber simdReg1, regNumber simdReg2, regNumber addrReg, emitter* emitter)
        : intReg1(intReg1)
        , simdReg1(simdReg1)
        , simdReg2(simdReg2)
        , addrReg(addrReg)
        , emitter(emitter)
    {
    }

    void LoadPairRegs(int offset, unsigned regSizeBytes)
    {
        assert((regSizeBytes == 8) || (regSizeBytes == 16));

        emitter->emitIns_R_R_R_I(INS_ldp, EA_SIZE(regSizeBytes), simdReg1, simdReg2, addrReg, offset);
    }

    void StorePairRegs(int offset, unsigned regSizeBytes)
    {
        assert((regSizeBytes == 8) || (regSizeBytes == 16));

        emitter->emitIns_R_R_R_I(INS_stp, EA_SIZE(regSizeBytes), simdReg1, simdReg2, addrReg, offset);
    }

    void LoadReg(int offset, unsigned regSizeBytes)
    {
        instruction ins = INS_ldr;

        // Note that 'intReg1' can be unavailable.
        // If that is the case, then use SIMD instruction ldr and
        // 'simdReg1' as a temporary register.
        regNumber tempReg;

        if ((regSizeBytes == 16) || (intReg1 == REG_NA))
        {
            tempReg = simdReg1;
        }
        else
        {
            tempReg = intReg1;

            if (regSizeBytes == 1)
            {
                ins = INS_ldrb;
            }
            else if (regSizeBytes == 2)
            {
                ins = INS_ldrh;
            }
        }

        emitter->emitIns_R_R_I(ins, EA_SIZE(regSizeBytes), tempReg, addrReg, offset);
    }

    void StoreReg(int offset, unsigned regSizeBytes)
    {
        instruction ins = INS_str;

        // Note that 'intReg1' can be unavailable.
        // If that is the case, then use SIMD instruction ldr and
        // 'simdReg1' as a temporary register.
        regNumber tempReg;

        if ((regSizeBytes == 16) || (intReg1 == REG_NA))
        {
            tempReg = simdReg1;
        }
        else
        {
            tempReg = intReg1;

            if (regSizeBytes == 1)
            {
                ins = INS_strb;
            }
            else if (regSizeBytes == 2)
            {
                ins = INS_strh;
            }
        }

        emitter->emitIns_R_R_I(ins, EA_SIZE(regSizeBytes), tempReg, addrReg, offset);
    }

private:
    const regNumber intReg1;
    const regNumber simdReg1;
    const regNumber simdReg2;
    const regNumber addrReg;
    emitter* const  emitter;
};

class BlockUnrollHelper
{
public:
    // The following function returns a 'size' bytes that
    //   1) is greater or equal to 'byteCount' and
    //   2) can be read or written by a single instruction on Arm64.
    // For example, Arm64 ISA has ldrb/strb and ldrh/strh that
    // load/store 1 or 2 bytes, correspondingly.
    // However, there are no instructions that can load/store 3 bytes and
    // the next "smallest" instruction is ldr/str that operates on 4 byte granularity.
    static unsigned GetRegSizeAtLeastBytes(unsigned byteCount)
    {
        assert(byteCount != 0);
        assert(byteCount < 16);

        unsigned regSizeBytes = byteCount;

        if (byteCount > 8)
        {
            regSizeBytes = 16;
        }
        else if (byteCount > 4)
        {
            regSizeBytes = 8;
        }
        else if (byteCount > 2)
        {
            regSizeBytes = 4;
        }

        return regSizeBytes;
    }
};

class InitBlockUnrollHelper
{
public:
    InitBlockUnrollHelper(int dstOffset, unsigned byteCount)
        : dstStartOffset(dstOffset)
        , byteCount(byteCount)
    {
    }

    int GetDstOffset() const
    {
        return dstStartOffset;
    }

    void SetDstOffset(int dstOffset)
    {
        dstStartOffset = dstOffset;
    }

    bool CanEncodeAllOffsets(int regSizeBytes) const
    {
        VerifyingStream instrStream;
        UnrollInitBlock(instrStream, regSizeBytes);

        return instrStream.CanEncodeAllStores();
    }

    unsigned InstructionCount(int regSizeBytes) const
    {
        CountingStream instrStream;
        UnrollInitBlock(instrStream, regSizeBytes);

        return instrStream.InstructionCount();
    }

    void Unroll(regNumber intReg, regNumber simdReg, regNumber addrReg, emitter* emitter) const
    {
        ProducingStream instrStream(intReg, simdReg, simdReg, addrReg, emitter);
        UnrollInitBlock(instrStream, FP_REGSIZE_BYTES);
    }

    void UnrollBaseInstrs(regNumber intReg, regNumber addrReg, emitter* emitter) const
    {
        ProducingStreamBaseInstrs instrStream(intReg, intReg, addrReg, emitter);
        UnrollInitBlock(instrStream, REGSIZE_BYTES);
    }

private:
    template <class InstructionStream>
    void UnrollInitBlock(InstructionStream& instrStream, int initialRegSizeBytes) const
    {
        assert((initialRegSizeBytes == 8) || (initialRegSizeBytes == 16));

        int       offset    = dstStartOffset;
        const int endOffset = offset + byteCount;

        const int storePairRegsAlignment   = initialRegSizeBytes;
        const int storePairRegsWritesBytes = 2 * initialRegSizeBytes;

        const int offsetAligned           = AlignUp((UINT)offset, storePairRegsAlignment);
        const int storePairRegsInstrCount = (endOffset - offsetAligned) / storePairRegsWritesBytes;

        if (storePairRegsInstrCount > 0)
        {
            if (offset != offsetAligned)
            {
                const int firstRegSizeBytes = BlockUnrollHelper::GetRegSizeAtLeastBytes(offsetAligned - offset);
                instrStream.StoreReg(offset, firstRegSizeBytes);
                offset = offsetAligned;
            }

            while (endOffset - offset >= storePairRegsWritesBytes)
            {
                instrStream.StorePairRegs(offset, initialRegSizeBytes);
                offset += storePairRegsWritesBytes;
            }

            if (endOffset - offset >= initialRegSizeBytes)
            {
                instrStream.StoreReg(offset, initialRegSizeBytes);
                offset += initialRegSizeBytes;
            }

            if (offset != endOffset)
            {
                const int lastRegSizeBytes = BlockUnrollHelper::GetRegSizeAtLeastBytes(endOffset - offset);
                instrStream.StoreReg(endOffset - lastRegSizeBytes, lastRegSizeBytes);
            }
        }
        else
        {
            bool isSafeToWriteBehind = false;

            while (endOffset - offset >= initialRegSizeBytes)
            {
                instrStream.StoreReg(offset, initialRegSizeBytes);
                offset += initialRegSizeBytes;
                isSafeToWriteBehind = true;
            }

            assert(endOffset - offset < initialRegSizeBytes);

            while (offset != endOffset)
            {
                if (isSafeToWriteBehind)
                {
                    assert(endOffset - offset < initialRegSizeBytes);
                    const int lastRegSizeBytes = BlockUnrollHelper::GetRegSizeAtLeastBytes(endOffset - offset);
                    instrStream.StoreReg(endOffset - lastRegSizeBytes, lastRegSizeBytes);
                    break;
                }

                if (offset + initialRegSizeBytes > endOffset)
                {
                    initialRegSizeBytes = initialRegSizeBytes / 2;
                }
                else
                {
                    instrStream.StoreReg(offset, initialRegSizeBytes);
                    offset += initialRegSizeBytes;
                    isSafeToWriteBehind = true;
                }
            }
        }
    }

    int            dstStartOffset;
    const unsigned byteCount;
};

class CopyBlockUnrollHelper
{
public:
    CopyBlockUnrollHelper(int srcOffset, int dstOffset, unsigned byteCount)
        : srcStartOffset(srcOffset)
        , dstStartOffset(dstOffset)
        , byteCount(byteCount)
    {
    }

    int GetSrcOffset() const
    {
        return srcStartOffset;
    }

    int GetDstOffset() const
    {
        return dstStartOffset;
    }

    void SetSrcOffset(int srcOffset)
    {
        srcStartOffset = srcOffset;
    }

    void SetDstOffset(int dstOffset)
    {
        dstStartOffset = dstOffset;
    }

    unsigned InstructionCount(int regSizeBytes) const
    {
        CountingStream instrStream;
        UnrollCopyBlock(instrStream, instrStream, regSizeBytes);

        return instrStream.InstructionCount();
    }

    bool CanEncodeAllOffsets(int regSizeBytes) const
    {
        bool canEncodeAllLoads  = true;
        bool canEncodeAllStores = true;

        TryEncodeAllOffsets(regSizeBytes, &canEncodeAllLoads, &canEncodeAllStores);
        return canEncodeAllLoads && canEncodeAllStores;
    }

    void TryEncodeAllOffsets(int regSizeBytes, bool* pCanEncodeAllLoads, bool* pCanEncodeAllStores) const
    {
        assert(pCanEncodeAllLoads != nullptr);
        assert(pCanEncodeAllStores != nullptr);

        VerifyingStream instrStream;
        UnrollCopyBlock(instrStream, instrStream, regSizeBytes);

        *pCanEncodeAllLoads  = instrStream.CanEncodeAllLoads();
        *pCanEncodeAllStores = instrStream.CanEncodeAllStores();
    }

    void Unroll(unsigned  initialRegSizeBytes,
                regNumber intReg,
                regNumber simdReg1,
                regNumber simdReg2,
                regNumber srcAddrReg,
                regNumber dstAddrReg,
                emitter*  emitter) const
    {
        ProducingStream loadStream(intReg, simdReg1, simdReg2, srcAddrReg, emitter);
        ProducingStream storeStream(intReg, simdReg1, simdReg2, dstAddrReg, emitter);
        UnrollCopyBlock(loadStream, storeStream, initialRegSizeBytes);
    }

    void UnrollBaseInstrs(
        regNumber intReg1, regNumber intReg2, regNumber srcAddrReg, regNumber dstAddrReg, emitter* emitter) const
    {
        ProducingStreamBaseInstrs loadStream(intReg1, intReg2, srcAddrReg, emitter);
        ProducingStreamBaseInstrs storeStream(intReg1, intReg2, dstAddrReg, emitter);
        UnrollCopyBlock(loadStream, storeStream, REGSIZE_BYTES);
    }

private:
    template <class InstructionStream>
    void UnrollCopyBlock(InstructionStream& loadStream, InstructionStream& storeStream, int initialRegSizeBytes) const
    {
        assert((initialRegSizeBytes == 8) || (initialRegSizeBytes == 16));

        int srcOffset = srcStartOffset;
        int dstOffset = dstStartOffset;

        const int endSrcOffset = srcOffset + byteCount;
        const int endDstOffset = dstOffset + byteCount;

        const int storePairRegsAlignment   = initialRegSizeBytes;
        const int storePairRegsWritesBytes = 2 * initialRegSizeBytes;

        const int dstOffsetAligned = AlignUp((UINT)dstOffset, storePairRegsAlignment);

        if (byteCount >= (unsigned)storePairRegsWritesBytes)
        {
            const int dstBytesToAlign = dstOffsetAligned - dstOffset;

            if (dstBytesToAlign != 0)
            {
                const int firstRegSizeBytes = BlockUnrollHelper::GetRegSizeAtLeastBytes(dstBytesToAlign);

                loadStream.LoadReg(srcOffset, firstRegSizeBytes);
                storeStream.StoreReg(dstOffset, firstRegSizeBytes);

                srcOffset = srcOffset + dstBytesToAlign;
                dstOffset = dstOffsetAligned;
            }

            while (endDstOffset - dstOffset >= storePairRegsWritesBytes)
            {
                loadStream.LoadPairRegs(srcOffset, initialRegSizeBytes);
                storeStream.StorePairRegs(dstOffset, initialRegSizeBytes);

                srcOffset += storePairRegsWritesBytes;
                dstOffset += storePairRegsWritesBytes;
            }

            if (endDstOffset - dstOffset >= initialRegSizeBytes)
            {
                loadStream.LoadReg(srcOffset, initialRegSizeBytes);
                storeStream.StoreReg(dstOffset, initialRegSizeBytes);

                srcOffset += initialRegSizeBytes;
                dstOffset += initialRegSizeBytes;
            }

            if (dstOffset != endDstOffset)
            {
                const int lastRegSizeBytes = BlockUnrollHelper::GetRegSizeAtLeastBytes(endDstOffset - dstOffset);

                loadStream.LoadReg(endSrcOffset - lastRegSizeBytes, lastRegSizeBytes);
                storeStream.StoreReg(endDstOffset - lastRegSizeBytes, lastRegSizeBytes);
            }
        }
        else
        {
            bool isSafeToWriteBehind = false;

            while (endDstOffset - dstOffset >= initialRegSizeBytes)
            {
                loadStream.LoadReg(srcOffset, initialRegSizeBytes);
                storeStream.StoreReg(dstOffset, initialRegSizeBytes);

                srcOffset += initialRegSizeBytes;
                dstOffset += initialRegSizeBytes;
                isSafeToWriteBehind = true;
            }

            assert(endSrcOffset - srcOffset < initialRegSizeBytes);

            while (dstOffset != endDstOffset)
            {
                if (isSafeToWriteBehind)
                {
                    const int lastRegSizeBytes = BlockUnrollHelper::GetRegSizeAtLeastBytes(endDstOffset - dstOffset);

                    loadStream.LoadReg(endSrcOffset - lastRegSizeBytes, lastRegSizeBytes);
                    storeStream.StoreReg(endDstOffset - lastRegSizeBytes, lastRegSizeBytes);
                    break;
                }

                if (dstOffset + initialRegSizeBytes > endDstOffset)
                {
                    initialRegSizeBytes = initialRegSizeBytes / 2;
                }
                else
                {
                    loadStream.LoadReg(srcOffset, initialRegSizeBytes);
                    storeStream.StoreReg(dstOffset, initialRegSizeBytes);

                    srcOffset += initialRegSizeBytes;
                    dstOffset += initialRegSizeBytes;
                    isSafeToWriteBehind = true;
                }
            }
        }
    }

    int            srcStartOffset;
    int            dstStartOffset;
    const unsigned byteCount;
};

#endif // TARGET_ARM64

//----------------------------------------------------------------------------------
// genCodeForInitBlkUnroll: Generate unrolled block initialization code.
//
// Arguments:
//    node - the GT_STORE_BLK node to generate code for
//
void CodeGen::genCodeForInitBlkUnroll(GenTreeBlk* node)
{
    assert(node->OperIs(GT_STORE_BLK));

    unsigned  dstLclNum      = BAD_VAR_NUM;
    regNumber dstAddrBaseReg = REG_NA;
    int       dstOffset      = 0;
    GenTree*  dstAddr        = node->Addr();

    if (!dstAddr->isContained())
    {
        dstAddrBaseReg = genConsumeReg(dstAddr);
    }
    else if (dstAddr->OperIsAddrMode())
    {
        assert(!dstAddr->AsAddrMode()->HasIndex());

        dstAddrBaseReg = genConsumeReg(dstAddr->AsAddrMode()->Base());
        dstOffset      = dstAddr->AsAddrMode()->Offset();
    }
    else
    {
        assert(dstAddr->OperIs(GT_LCL_ADDR));
        dstLclNum = dstAddr->AsLclVarCommon()->GetLclNum();
        dstOffset = dstAddr->AsLclVarCommon()->GetLclOffs();
    }

    GenTree* src = node->Data();

    if (src->OperIs(GT_INIT_VAL))
    {
        assert(src->isContained());
        src = src->gtGetOp1();
    }

    if (node->IsVolatile())
    {
        instGen_MemoryBarrier();
    }

    emitter* emit = GetEmitter();
    unsigned size = node->GetLayout()->GetSize();

    assert(size <= INT32_MAX);
    assert(dstOffset < INT32_MAX - static_cast<int>(size));

#ifdef TARGET_ARM64
    InitBlockUnrollHelper helper(dstOffset, size);

    regNumber srcReg;

    if (!src->isContained())
    {
        srcReg = genConsumeReg(src);
    }
    else
    {
        assert(src->IsIntegralConst(0));
        srcReg = REG_ZR;
    }

    regNumber dstReg              = dstAddrBaseReg;
    int       dstRegAddrAlignment = 0;

    if (dstLclNum != BAD_VAR_NUM)
    {
        bool      fpBased;
        const int baseAddr = compiler->lvaFrameAddress(dstLclNum, &fpBased);

        dstReg              = fpBased ? REG_FPBASE : REG_SPBASE;
        dstRegAddrAlignment = fpBased ? (genSPtoFPdelta() % 16) : 0;

        helper.SetDstOffset(baseAddr + dstOffset);
    }

    if (!helper.CanEncodeAllOffsets(REGSIZE_BYTES))
    {
        // If dstRegAddrAlignment is known and non-zero the following ensures that the adjusted value of dstReg is at
        // 16-byte aligned boundary.
        // This is done to potentially allow more cases where the JIT can use 16-byte stores.
        const int dstOffsetAdjustment = helper.GetDstOffset() - dstRegAddrAlignment;
        dstRegAddrAlignment           = 0;

        const regNumber tempReg = node->ExtractTempReg(RBM_ALLINT);
        genInstrWithConstant(INS_add, EA_PTRSIZE, tempReg, dstReg, dstOffsetAdjustment, tempReg);
        dstReg = tempReg;

        helper.SetDstOffset(helper.GetDstOffset() - dstOffsetAdjustment);
    }

    bool shouldUse16ByteWideInstrs = false;

    const bool hasAvailableSimdReg = (size > FP_REGSIZE_BYTES);
    const bool canUse16ByteWideInstrs =
        hasAvailableSimdReg && (dstRegAddrAlignment == 0) && helper.CanEncodeAllOffsets(FP_REGSIZE_BYTES);

    if (canUse16ByteWideInstrs)
    {
        // The JIT would need to initialize a SIMD register with "movi simdReg.16B, #initValue".
        const unsigned instrCount16ByteWide = helper.InstructionCount(FP_REGSIZE_BYTES) + 1;
        shouldUse16ByteWideInstrs           = instrCount16ByteWide < helper.InstructionCount(REGSIZE_BYTES);
    }

    if (shouldUse16ByteWideInstrs)
    {
        const regNumber simdReg = node->GetSingleTempReg(RBM_ALLFLOAT);

        const int initValue = (src->AsIntCon()->IconValue() & 0xFF);
        emit->emitIns_R_I(INS_movi, EA_16BYTE, simdReg, initValue, INS_OPTS_16B);

        helper.Unroll(srcReg, simdReg, dstReg, GetEmitter());
    }
    else
    {
        helper.UnrollBaseInstrs(srcReg, dstReg, GetEmitter());
    }
#endif // TARGET_ARM64

#ifdef TARGET_ARM
    const regNumber srcReg = genConsumeReg(src);

    for (unsigned regSize = REGSIZE_BYTES; size > 0; size -= regSize, dstOffset += regSize)
    {
        while (regSize > size)
        {
            regSize /= 2;
        }

        instruction storeIns;
        emitAttr    attr;

        switch (regSize)
        {
            case 1:
                storeIns = INS_strb;
                attr     = EA_4BYTE;
                break;
            case 2:
                storeIns = INS_strh;
                attr     = EA_4BYTE;
                break;
            case 4:
                storeIns = INS_str;
                attr     = EA_ATTR(regSize);
                break;
            default:
                unreached();
        }

        if (dstLclNum != BAD_VAR_NUM)
        {
            emit->emitIns_S_R(storeIns, attr, srcReg, dstLclNum, dstOffset);
        }
        else
        {
            emit->emitIns_R_R_I(storeIns, attr, srcReg, dstAddrBaseReg, dstOffset);
        }
    }
#endif // TARGET_ARM
}

//----------------------------------------------------------------------------------
// genCodeForCpBlkUnroll: Generate unrolled block copy code.
//
// Arguments:
//    node - the GT_STORE_BLK node to generate code for
//
void CodeGen::genCodeForCpBlkUnroll(GenTreeBlk* node)
{
    assert(node->OperIs(GT_STORE_BLK));

    unsigned  dstLclNum      = BAD_VAR_NUM;
    regNumber dstAddrBaseReg = REG_NA;
    int       dstOffset      = 0;
    GenTree*  dstAddr        = node->Addr();

    if (!dstAddr->isContained())
    {
        dstAddrBaseReg = genConsumeReg(dstAddr);
    }
    else if (dstAddr->OperIsAddrMode())
    {
        assert(!dstAddr->AsAddrMode()->HasIndex());

        dstAddrBaseReg = genConsumeReg(dstAddr->AsAddrMode()->Base());
        dstOffset      = dstAddr->AsAddrMode()->Offset();
    }
    else
    {
        assert(dstAddr->OperIs(GT_LCL_ADDR));
        dstLclNum = dstAddr->AsLclVarCommon()->GetLclNum();
        dstOffset = dstAddr->AsLclVarCommon()->GetLclOffs();
    }

    unsigned  srcLclNum      = BAD_VAR_NUM;
    regNumber srcAddrBaseReg = REG_NA;
    int       srcOffset      = 0;
    GenTree*  src            = node->Data();

    assert(src->isContained());

    if (src->OperIs(GT_LCL_VAR, GT_LCL_FLD))
    {
        srcLclNum = src->AsLclVarCommon()->GetLclNum();
        srcOffset = src->AsLclVarCommon()->GetLclOffs();
    }
    else
    {
        assert(src->OperIs(GT_IND));
        GenTree* srcAddr = src->AsIndir()->Addr();

        if (!srcAddr->isContained())
        {
            srcAddrBaseReg = genConsumeReg(srcAddr);
        }
        else if (srcAddr->OperIsAddrMode())
        {
            srcAddrBaseReg = genConsumeReg(srcAddr->AsAddrMode()->Base());
            srcOffset      = srcAddr->AsAddrMode()->Offset();
        }
        else
        {
            assert(srcAddr->OperIs(GT_LCL_ADDR));
            srcLclNum = srcAddr->AsLclVarCommon()->GetLclNum();
            srcOffset = srcAddr->AsLclVarCommon()->GetLclOffs();
        }
    }

    if (node->IsVolatile())
    {
        // issue a full memory barrier before a volatile CpBlk operation
        instGen_MemoryBarrier();
    }

    emitter* emit = GetEmitter();
    unsigned size = node->GetLayout()->GetSize();

    assert(size <= INT32_MAX);
    assert(srcOffset < INT32_MAX - static_cast<int>(size));
    assert(dstOffset < INT32_MAX - static_cast<int>(size));

#ifdef TARGET_ARM64
    CopyBlockUnrollHelper helper(srcOffset, dstOffset, size);
    regNumber             srcReg = srcAddrBaseReg;

    if (srcLclNum != BAD_VAR_NUM)
    {
        bool      fpBased;
        const int baseAddr = compiler->lvaFrameAddress(srcLclNum, &fpBased);

        srcReg = fpBased ? REG_FPBASE : REG_SPBASE;
        helper.SetSrcOffset(baseAddr + srcOffset);
    }

    regNumber dstReg = dstAddrBaseReg;

    if (dstLclNum != BAD_VAR_NUM)
    {
        bool      fpBased;
        const int baseAddr = compiler->lvaFrameAddress(dstLclNum, &fpBased);

        dstReg = fpBased ? REG_FPBASE : REG_SPBASE;
        helper.SetDstOffset(baseAddr + dstOffset);
    }

    bool canEncodeAllLoads  = true;
    bool canEncodeAllStores = true;
    helper.TryEncodeAllOffsets(REGSIZE_BYTES, &canEncodeAllLoads, &canEncodeAllStores);

    srcOffset = helper.GetSrcOffset();
    dstOffset = helper.GetDstOffset();

    int srcOffsetAdjustment = 0;
    int dstOffsetAdjustment = 0;

    if (!canEncodeAllLoads && !canEncodeAllStores)
    {
        srcOffsetAdjustment = srcOffset;
        dstOffsetAdjustment = dstOffset;
    }
    else if (!canEncodeAllLoads)
    {
        srcOffsetAdjustment = srcOffset - dstOffset;
    }
    else if (!canEncodeAllStores)
    {
        dstOffsetAdjustment = dstOffset - srcOffset;
    }

    helper.SetSrcOffset(srcOffset - srcOffsetAdjustment);
    helper.SetDstOffset(dstOffset - dstOffsetAdjustment);

    // Quad-word load operations that are not 16-byte aligned, and store operations that cross a 16-byte boundary
    // can reduce bandwidth or incur additional latency.
    // Therefore, the JIT would attempt to use 16-byte variants of such instructions when both conditions are met:
    //   1) the base address stored in dstReg has known alignment (modulo 16 bytes) and
    //   2) the base address stored in srcReg has the same alignment as the address in dstReg.
    //
    // When both addresses are 16-byte aligned the CopyBlock instruction sequence looks like
    //
    // ldp Q_simdReg1, Q_simdReg2, [srcReg, #srcOffset]
    // stp Q_simdReg1, Q_simdReg2, [dstReg, #dstOffset]
    // ldp Q_simdReg1, Q_simdReg2, [srcReg, #dstOffset+32]
    // stp Q_simdReg1, Q_simdReg2, [dstReg, #dstOffset+32]
    // ...
    //
    // When both addresses are not 16-byte aligned the CopyBlock instruction sequence starts with padding
    // str instruction. For example, when both addresses are 8-byte aligned the instruction sequence looks like
    //
    // ldr X_intReg1, [srcReg, #srcOffset]
    // str X_intReg1, [dstReg, #dstOffset]
    // ldp Q_simdReg1, Q_simdReg2, [srcReg, #srcOffset+8]
    // stp Q_simdReg1, Q_simdReg2, [dstReg, #dstOffset+8]
    // ldp Q_simdReg1, Q_simdReg2, [srcReg, #srcOffset+40]
    // stp Q_simdReg1, Q_simdReg2, [dstReg, #dstOffset+40]
    // ...

    // LSRA allocates a pair of SIMD registers when alignments of both source and destination base addresses are
    // known and the block size is larger than a single SIMD register size (i.e. when using SIMD instructions can
    // be profitable).

    const bool canUse16ByteWideInstrs = (size >= 2 * FP_REGSIZE_BYTES);

    bool shouldUse16ByteWideInstrs = false;

    if (canUse16ByteWideInstrs)
    {
        bool canEncodeAll16ByteWideLoads  = false;
        bool canEncodeAll16ByteWideStores = false;
        helper.TryEncodeAllOffsets(FP_REGSIZE_BYTES, &canEncodeAll16ByteWideLoads, &canEncodeAll16ByteWideStores);

        if (canEncodeAll16ByteWideLoads && canEncodeAll16ByteWideStores)
        {
            // No further adjustments for srcOffset and dstOffset are needed.
            // The JIT should use 16-byte loads and stores when the resulting sequence has fewer number of instructions.

            shouldUse16ByteWideInstrs =
                (helper.InstructionCount(FP_REGSIZE_BYTES) < helper.InstructionCount(REGSIZE_BYTES));
        }
        else if (canEncodeAllLoads && canEncodeAllStores &&
                 (canEncodeAll16ByteWideLoads || canEncodeAll16ByteWideStores))
        {
            // In order to use 16-byte instructions the JIT needs to adjust either srcOffset or dstOffset.
            // The JIT should use 16-byte loads and stores when the resulting sequence (incl. an additional add
            // instruction) has fewer number of instructions.

            if (helper.InstructionCount(FP_REGSIZE_BYTES) + 1 < helper.InstructionCount(REGSIZE_BYTES))
            {
                shouldUse16ByteWideInstrs = true;

                if (!canEncodeAll16ByteWideLoads)
                {
                    srcOffsetAdjustment = srcOffset - dstOffset;
                }
                else
                {
                    dstOffsetAdjustment = dstOffset - srcOffset;
                }

                helper.SetSrcOffset(srcOffset - srcOffsetAdjustment);
                helper.SetDstOffset(dstOffset - dstOffsetAdjustment);
            }
        }
    }

#ifdef DEBUG
    if (shouldUse16ByteWideInstrs)
    {
        assert(helper.CanEncodeAllOffsets(FP_REGSIZE_BYTES));
    }
    else
    {
        assert(helper.CanEncodeAllOffsets(REGSIZE_BYTES));
    }
#endif

    if (!node->gtBlkOpGcUnsafe && ((srcOffsetAdjustment != 0) || (dstOffsetAdjustment != 0)))
    {
        // If node is not already marked as non-interruptible, and if are about to generate code
        // that produce GC references in temporary registers not reported, then mark the block
        // as non-interruptible.
        // Corresponding EnableGC() will be done by the caller of this method.
        node->gtBlkOpGcUnsafe = true;
        GetEmitter()->emitDisableGC();
    }

    if ((srcOffsetAdjustment != 0) && (dstOffsetAdjustment != 0))
    {
        const regNumber tempReg1 = node->ExtractTempReg(RBM_ALLINT);
        genInstrWithConstant(INS_add, EA_PTRSIZE, tempReg1, srcReg, srcOffsetAdjustment, tempReg1);
        srcReg = tempReg1;

        const regNumber tempReg2 = node->ExtractTempReg(RBM_ALLINT);
        genInstrWithConstant(INS_add, EA_PTRSIZE, tempReg2, dstReg, dstOffsetAdjustment, tempReg2);
        dstReg = tempReg2;
    }
    else if (srcOffsetAdjustment != 0)
    {
        const regNumber tempReg = node->ExtractTempReg(RBM_ALLINT);
        genInstrWithConstant(INS_add, EA_PTRSIZE, tempReg, srcReg, srcOffsetAdjustment, tempReg);
        srcReg = tempReg;
    }
    else if (dstOffsetAdjustment != 0)
    {
        const regNumber tempReg = node->ExtractTempReg(RBM_ALLINT);
        genInstrWithConstant(INS_add, EA_PTRSIZE, tempReg, dstReg, dstOffsetAdjustment, tempReg);
        dstReg = tempReg;
    }

    regNumber intReg1 = REG_NA;
    regNumber intReg2 = REG_NA;

    const unsigned intRegCount = node->AvailableTempRegCount(RBM_ALLINT);

    if (intRegCount >= 2)
    {
        intReg1 = node->ExtractTempReg(RBM_ALLINT);
        intReg2 = node->ExtractTempReg(RBM_ALLINT);
    }
    else if (intRegCount == 1)
    {
        intReg1 = node->GetSingleTempReg(RBM_ALLINT);
        intReg2 = rsGetRsvdReg();
    }
    else
    {
        intReg1 = rsGetRsvdReg();
    }

    if (shouldUse16ByteWideInstrs)
    {
        const regNumber simdReg1 = node->ExtractTempReg(RBM_ALLFLOAT);
        const regNumber simdReg2 = node->GetSingleTempReg(RBM_ALLFLOAT);

        helper.Unroll(FP_REGSIZE_BYTES, intReg1, simdReg1, simdReg2, srcReg, dstReg, GetEmitter());
    }
    else
    {
        helper.UnrollBaseInstrs(intReg1, intReg2, srcReg, dstReg, GetEmitter());
    }
#endif // TARGET_ARM64

#ifdef TARGET_ARM
    const regNumber tempReg = node->ExtractTempReg(RBM_ALLINT);

    for (unsigned regSize = REGSIZE_BYTES; size > 0; size -= regSize, srcOffset += regSize, dstOffset += regSize)
    {
        while (regSize > size)
        {
            regSize /= 2;
        }

        instruction loadIns;
        instruction storeIns;
        emitAttr    attr;

        switch (regSize)
        {
            case 1:
                loadIns  = INS_ldrb;
                storeIns = INS_strb;
                attr     = EA_4BYTE;
                break;
            case 2:
                loadIns  = INS_ldrh;
                storeIns = INS_strh;
                attr     = EA_4BYTE;
                break;
            case 4:
                loadIns  = INS_ldr;
                storeIns = INS_str;
                attr     = EA_ATTR(regSize);
                break;
            default:
                unreached();
        }

        if (srcLclNum != BAD_VAR_NUM)
        {
            emit->emitIns_R_S(loadIns, attr, tempReg, srcLclNum, srcOffset);
        }
        else
        {
            emit->emitIns_R_R_I(loadIns, attr, tempReg, srcAddrBaseReg, srcOffset);
        }

        if (dstLclNum != BAD_VAR_NUM)
        {
            emit->emitIns_S_R(storeIns, attr, tempReg, dstLclNum, dstOffset);
        }
        else
        {
            emit->emitIns_R_R_I(storeIns, attr, tempReg, dstAddrBaseReg, dstOffset);
        }
    }
#endif // TARGET_ARM

    if (node->IsVolatile())
    {
        // issue a load barrier after a volatile CpBlk operation
        instGen_MemoryBarrier(BARRIER_LOAD_ONLY);
    }
}

//------------------------------------------------------------------------
// genCodeForMemmove: Perform an unrolled memmove. The idea that we can
//    ignore the fact that src and dst might overlap if we save the whole
//    src to temp regs in advance, e.g. for memmove(dst: x1, src: x0, len: 30):
//
//       ldr   q16, [x0]
//       ldr   q17, [x0, #0x0E]
//       str   q16, [x1]
//       str   q17, [x1, #0x0E]
//
// Arguments:
//    tree - GenTreeBlk node
//
void CodeGen::genCodeForMemmove(GenTreeBlk* tree)
{
#ifdef TARGET_ARM64
    // TODO-CQ: Support addressing modes, for now we don't use them
    GenTreeIndir* srcIndir = tree->Data()->AsIndir();
    assert(srcIndir->isContained() && !srcIndir->Addr()->isContained());

    regNumber dst  = genConsumeReg(tree->Addr());
    regNumber src  = genConsumeReg(srcIndir->Addr());
    unsigned  size = tree->Size();

    auto emitLoadStore = [&](bool load, unsigned regSize, regNumber tempReg, unsigned offset) {
        var_types memType;
        switch (regSize)
        {
            case 1:
                memType = TYP_UBYTE;
                break;
            case 2:
                memType = TYP_USHORT;
                break;
            case 4:
                memType = TYP_INT;
                break;
            case 8:
                memType = TYP_LONG;
                break;
            case 16:
                memType = TYP_SIMD16;
                break;
            default:
                unreached();
        }
        if (load)
        {
            GetEmitter()->emitIns_R_R_I(ins_Load(memType), emitTypeSize(memType), tempReg, src, offset);
        }
        else
        {
            GetEmitter()->emitIns_R_R_I(ins_Store(memType), emitTypeSize(memType), tempReg, dst, offset);
        }
    };

    // Eventually, we'll emit CPYP+CPYM+CPYE on armv9 for large sizes here.

    // Let's not use stp/ldp here and rely on the underlying peephole optimizations to merge subsequent
    // ldr/str pairs into stp/ldp, see https://github.com/dotnet/runtime/issues/64815
    unsigned simdSize = FP_REGSIZE_BYTES;
    if (size >= simdSize)
    {
        // Number of SIMD regs needed to save the whole src to regs.
        const unsigned numberOfSimdRegs = tree->AvailableTempRegCount(RBM_ALLFLOAT);

        // Pop all temp regs to a local array, currently, this impl is limited with LSRA's MaxInternalCount
        regNumber tempRegs[LinearScan::MaxInternalCount] = {};
        for (unsigned i = 0; i < numberOfSimdRegs; i++)
        {
            tempRegs[i] = tree->ExtractTempReg(RBM_ALLFLOAT);
        }

        auto emitSimdLoadStore = [&](bool load) {
            unsigned offset   = 0;
            int      regIndex = 0;
            do
            {
                emitLoadStore(load, simdSize, tempRegs[regIndex++], offset);
                offset += simdSize;
                if (size == offset)
                {
                    break;
                }
                if ((size - offset) < simdSize)
                {
                    // Overlap with the previously processed data. We'll always use SIMD for simplicity
                    // TODO-CQ: Consider using smaller SIMD reg or GPR for the remainder.
                    offset = size - simdSize;
                }
            } while (true);
        };

        // load everything from SRC to temp regs
        emitSimdLoadStore(/* load */ true);
        // store them to DST
        emitSimdLoadStore(/* load */ false);
    }
    else
    {
        // Here we work with size 1..15
        assert((size > 0) && (size < FP_REGSIZE_BYTES));

        // Use overlapping loads/stores, e. g. for size == 9: "ldr x2, [x0]; ldr x3, [x0, #0x01]".
        const unsigned loadStoreSize = 1 << BitOperations::Log2(size);
        if (loadStoreSize == size)
        {
            const regNumber tmpReg = tree->GetSingleTempReg(RBM_ALLINT);
            emitLoadStore(/* load */ true, loadStoreSize, tmpReg, 0);
            emitLoadStore(/* load */ false, loadStoreSize, tmpReg, 0);
        }
        else
        {
            assert(tree->AvailableTempRegCount() == 2);
            const regNumber tmpReg1 = tree->ExtractTempReg(RBM_ALLINT);
            const regNumber tmpReg2 = tree->ExtractTempReg(RBM_ALLINT);
            emitLoadStore(/* load */ true, loadStoreSize, tmpReg1, 0);
            emitLoadStore(/* load */ true, loadStoreSize, tmpReg2, size - loadStoreSize);
            emitLoadStore(/* load */ false, loadStoreSize, tmpReg1, 0);
            emitLoadStore(/* load */ false, loadStoreSize, tmpReg2, size - loadStoreSize);
        }
    }
#else // TARGET_ARM64
    unreached();
#endif
}

//------------------------------------------------------------------------
// genCodeForInitBlkLoop - Generate code for an InitBlk using an inlined for-loop.
//    It's needed for cases when size is too big to unroll and we're not allowed
//    to use memset call due to atomicity requirements.
//
// Arguments:
//    initBlkNode - the GT_STORE_BLK node
//
void CodeGen::genCodeForInitBlkLoop(GenTreeBlk* initBlkNode)
{
    GenTree* const dstNode = initBlkNode->Addr();
    genConsumeReg(dstNode);
    const regNumber dstReg = dstNode->GetRegNum();

#ifndef TARGET_ARM64
    GenTree* const zeroNode = initBlkNode->Data();
    genConsumeReg(zeroNode);
    const regNumber zeroReg = zeroNode->GetRegNum();
#else
    const regNumber zeroReg = REG_ZR;
#endif

    if (initBlkNode->IsVolatile())
    {
        // issue a full memory barrier before a volatile initBlock Operation
        instGen_MemoryBarrier();
    }

    //  str     xzr, [dstReg]
    //  mov     offsetReg, <block size>
    //.LOOP:
    //  str     xzr, [dstReg, offsetReg]
    //  subs    offsetReg, offsetReg, #8
    //  bne     .LOOP

    const unsigned size = initBlkNode->GetLayout()->GetSize();
    assert((size >= TARGET_POINTER_SIZE) && ((size % TARGET_POINTER_SIZE) == 0));

    // The loop is reversed - it makes it smaller.
    // Although, we zero the first pointer before the loop (the loop doesn't zero it)
    // it works as a nullcheck, otherwise the first iteration would try to access
    // "null + potentially large offset" and hit AV.
    GetEmitter()->emitIns_R_R(INS_str, EA_PTRSIZE, zeroReg, dstReg);
    if (size > TARGET_POINTER_SIZE)
    {
        // Extend liveness of dstReg in case if it gets killed by the store.
        gcInfo.gcMarkRegPtrVal(dstReg, dstNode->TypeGet());

        const regNumber offsetReg = initBlkNode->GetSingleTempReg();
        instGen_Set_Reg_To_Imm(EA_PTRSIZE, offsetReg, size - TARGET_POINTER_SIZE);

        BasicBlock* loop = genCreateTempLabel();
        genDefineTempLabel(loop);

        GetEmitter()->emitIns_R_R_R(INS_str, EA_PTRSIZE, zeroReg, dstReg, offsetReg);
#ifdef TARGET_ARM64
        GetEmitter()->emitIns_R_R_I(INS_subs, EA_PTRSIZE, offsetReg, offsetReg, TARGET_POINTER_SIZE);
#else
        GetEmitter()->emitIns_R_R_I(INS_sub, EA_PTRSIZE, offsetReg, offsetReg, TARGET_POINTER_SIZE, INS_FLAGS_SET);
#endif
        inst_JMP(EJ_ne, loop);

        gcInfo.gcMarkRegSetNpt(genRegMask(dstReg));
    }
}

//------------------------------------------------------------------------
// genCall: Produce code for a GT_CALL node
//
void CodeGen::genCall(GenTreeCall* call)
{
    // Consume all the arg regs
    for (CallArg& arg : call->gtArgs.LateArgs())
    {
        CallArgABIInformation& abiInfo = arg.AbiInfo;
        GenTree*               argNode = arg.GetLateNode();

        if (abiInfo.GetRegNum() == REG_STK)
            continue;

        // Deal with multi register passed struct args.
        if (argNode->OperGet() == GT_FIELD_LIST)
        {
            regNumber argReg = abiInfo.GetRegNum();
            for (GenTreeFieldList::Use& use : argNode->AsFieldList()->Uses())
            {
                GenTree* putArgRegNode = use.GetNode();
                assert(putArgRegNode->gtOper == GT_PUTARG_REG);

                genConsumeReg(putArgRegNode);
                inst_Mov_Extend(putArgRegNode->TypeGet(), /* srcInReg */ true, argReg, putArgRegNode->GetRegNum(),
                                /* canSkip */ true, emitActualTypeSize(TYP_I_IMPL));

                argReg = genRegArgNext(argReg);

#if defined(TARGET_ARM)
                // A double register is modelled as an even-numbered single one
                if (putArgRegNode->TypeGet() == TYP_DOUBLE)
                {
                    argReg = genRegArgNext(argReg);
                }
#endif // TARGET_ARM
            }
        }
        else if (abiInfo.IsSplit())
        {
            assert(compFeatureArgSplit());
            assert(abiInfo.NumRegs >= 1);
            genConsumeArgSplitStruct(argNode->AsPutArgSplit());
            for (unsigned idx = 0; idx < abiInfo.NumRegs; idx++)
            {
                regNumber argReg   = (regNumber)((unsigned)abiInfo.GetRegNum() + idx);
                regNumber allocReg = argNode->AsPutArgSplit()->GetRegNumByIdx(idx);
                inst_Mov_Extend(argNode->TypeGet(), /* srcInReg */ true, argReg, allocReg, /* canSkip */ true,
                                emitActualTypeSize(TYP_I_IMPL));
            }
        }
        else
        {
            regNumber argReg = abiInfo.GetRegNum();
            genConsumeReg(argNode);
            inst_Mov_Extend(argNode->TypeGet(), /* srcInReg */ true, argReg, argNode->GetRegNum(), /* canSkip */ true,
                            emitActualTypeSize(TYP_I_IMPL));
        }
    }

    // Insert a null check on "this" pointer if asked.
    if (call->NeedsNullCheck())
    {
        const regNumber regThis = genGetThisArgReg(call);

#if defined(TARGET_ARM)
        const regNumber tmpReg = call->ExtractTempReg();
        GetEmitter()->emitIns_R_R_I(INS_ldr, EA_4BYTE, tmpReg, regThis, 0);
#elif defined(TARGET_ARM64)
        GetEmitter()->emitIns_R_R_I(INS_ldr, EA_4BYTE, REG_ZR, regThis, 0);
#endif // TARGET*
    }

    // If fast tail call, then we are done here, we just have to load the call
    // target into the right registers. We ensure in RA that target is loaded
    // into a volatile register that won't be restored by epilog sequence.
    if (call->IsFastTailCall())
    {
        GenTree* target = getCallTarget(call, nullptr);

        if (target != nullptr)
        {
            // Indirect fast tail calls materialize call target either in gtControlExpr or in gtCallAddr.
            genConsumeReg(target);
        }
#ifdef FEATURE_READYTORUN
        else if (call->IsR2ROrVirtualStubRelativeIndir())
        {
            assert((call->IsR2RRelativeIndir() && (call->gtEntryPoint.accessType == IAT_PVALUE)) ||
                   (call->IsVirtualStubRelativeIndir() && (call->gtEntryPoint.accessType == IAT_VALUE)));
            assert(call->gtControlExpr == nullptr);

            regNumber tmpReg = call->GetSingleTempReg();
            // Register where we save call address in should not be overridden by epilog.
            assert((genRegMask(tmpReg) & (RBM_INT_CALLEE_TRASH & ~RBM_LR)) == genRegMask(tmpReg));

            regNumber callAddrReg =
                call->IsVirtualStubRelativeIndir() ? compiler->virtualStubParamInfo->GetReg() : REG_R2R_INDIRECT_PARAM;
            GetEmitter()->emitIns_R_R(ins_Load(TYP_I_IMPL), emitActualTypeSize(TYP_I_IMPL), tmpReg, callAddrReg);
            // We will use this again when emitting the jump in genCallInstruction in the epilog
            call->gtRsvdRegs |= genRegMask(tmpReg);
        }
#endif

        return;
    }

    // For a pinvoke to unmanaged code we emit a label to clear
    // the GC pointer state before the callsite.
    // We can't utilize the typical lazy killing of GC pointers
    // at (or inside) the callsite.
    if (compiler->killGCRefs(call))
    {
        genDefineTempLabel(genCreateTempLabel());
    }

    genCallInstruction(call);

    genDefinePendingCallLabel(call);

#ifdef DEBUG
    // We should not have GC pointers in killed registers live around the call.
    // GC info for arg registers were cleared when consuming arg nodes above
    // and LSRA should ensure it for other trashed registers.
    regMaskTP killMask = RBM_CALLEE_TRASH;
    if (call->IsHelperCall())
    {
        CorInfoHelpFunc helpFunc = compiler->eeGetHelperNum(call->gtCallMethHnd);
        killMask                 = compiler->compHelperCallKillSet(helpFunc);
    }

    assert((gcInfo.gcRegGCrefSetCur & killMask) == 0);
    assert((gcInfo.gcRegByrefSetCur & killMask) == 0);
#endif

    var_types returnType = call->TypeGet();
    if (returnType != TYP_VOID)
    {
        regNumber returnReg;

        if (call->HasMultiRegRetVal())
        {
            const ReturnTypeDesc* pRetTypeDesc = call->GetReturnTypeDesc();
            assert(pRetTypeDesc != nullptr);
            unsigned regCount = pRetTypeDesc->GetReturnRegCount();

            // If regs allocated to call node are different from ABI return
            // regs in which the call has returned its result, move the result
            // to regs allocated to call node.
            for (unsigned i = 0; i < regCount; ++i)
            {
                var_types regType      = pRetTypeDesc->GetReturnRegType(i);
                returnReg              = pRetTypeDesc->GetABIReturnReg(i, call->GetUnmanagedCallConv());
                regNumber allocatedReg = call->GetRegNumByIdx(i);
                inst_Mov(regType, allocatedReg, returnReg, /* canSkip */ true);
            }
        }
        else
        {
#ifdef TARGET_ARM
            if (call->IsHelperCall(compiler, CORINFO_HELP_INIT_PINVOKE_FRAME))
            {
                // The CORINFO_HELP_INIT_PINVOKE_FRAME helper uses a custom calling convention that returns with
                // TCB in REG_PINVOKE_TCB. fgMorphCall() sets the correct argument registers.
                returnReg = REG_PINVOKE_TCB;
            }
            else if (compiler->opts.compUseSoftFP)
            {
                returnReg = REG_INTRET;
            }
            else
#endif // TARGET_ARM
                if (varTypeUsesFloatArgReg(returnType))
                {
                    returnReg = REG_FLOATRET;
                }
                else
                {
                    returnReg = REG_INTRET;
                }

            if (call->GetRegNum() != returnReg)
            {
#ifdef TARGET_ARM
                if (compiler->opts.compUseSoftFP && returnType == TYP_DOUBLE)
                {
                    inst_RV_RV_RV(INS_vmov_i2d, call->GetRegNum(), returnReg, genRegArgNext(returnReg), EA_8BYTE);
                }
                else if (compiler->opts.compUseSoftFP && returnType == TYP_FLOAT)
                {
                    inst_Mov(returnType, call->GetRegNum(), returnReg, /* canSkip */ false);
                }
                else
#endif
                {
                    inst_Mov(returnType, call->GetRegNum(), returnReg, /* canSkip */ false);
                }
            }
        }

        genProduceReg(call);
    }

    // If there is nothing next, that means the result is thrown away, so this value is not live.
    // However, for minopts or debuggable code, we keep it live to support managed return value debugging.
    if ((call->gtNext == nullptr) && !compiler->opts.MinOpts() && !compiler->opts.compDbgCode)
    {
        gcInfo.gcMarkRegSetNpt(RBM_INTRET);
    }
}

//------------------------------------------------------------------------
// genCallInstruction - Generate instructions necessary to transfer control to the call.
//
// Arguments:
//    call - the GT_CALL node
//
// Remaks:
//   For tailcalls this function will generate a jump.
//
void CodeGen::genCallInstruction(GenTreeCall* call)
{
    // Determine return value size(s).
    const ReturnTypeDesc* pRetTypeDesc  = call->GetReturnTypeDesc();
    emitAttr              retSize       = EA_PTRSIZE;
    emitAttr              secondRetSize = EA_UNKNOWN;

    // unused values are of no interest to GC.
    if (!call->IsUnusedValue())
    {
        if (call->HasMultiRegRetVal())
        {
            retSize       = emitTypeSize(pRetTypeDesc->GetReturnRegType(0));
            secondRetSize = emitTypeSize(pRetTypeDesc->GetReturnRegType(1));
        }
        else
        {
            assert(call->gtType != TYP_STRUCT);

            if (call->gtType == TYP_REF)
            {
                retSize = EA_GCREF;
            }
            else if (call->gtType == TYP_BYREF)
            {
                retSize = EA_BYREF;
            }
        }
    }

#ifdef TARGET_ARM
    // ARM32 support multireg returns, but only to return 64bit primitives.
    assert(secondRetSize != EA_GCREF);
    assert(secondRetSize != EA_BYREF);
#endif

    DebugInfo di;
    // We need to propagate the debug information to the call instruction, so we can emit
    // an IL to native mapping record for the call, to support managed return value debugging.
    // We don't want tail call helper calls that were converted from normal calls to get a record,
    // so we skip this hash table lookup logic in that case.
    if (compiler->opts.compDbgInfo && compiler->genCallSite2DebugInfoMap != nullptr && !call->IsTailCall())
    {
        (void)compiler->genCallSite2DebugInfoMap->Lookup(call, &di);
    }

    CORINFO_SIG_INFO* sigInfo = nullptr;
#ifdef DEBUG
    // Pass the call signature information down into the emitter so the emitter can associate
    // native call sites with the signatures they were generated from.
    if (!call->IsHelperCall())
    {
        sigInfo = call->callSig;
    }

    if (call->IsFastTailCall())
    {
        regMaskTP trashedByEpilog = RBM_CALLEE_SAVED;

        // The epilog may use and trash REG_GSCOOKIE_TMP_0/1. Make sure we have no
        // non-standard args that may be trash if this is a tailcall.
        if (compiler->getNeedsGSSecurityCookie())
        {
            trashedByEpilog |= genRegMask(REG_GSCOOKIE_TMP_0);
            trashedByEpilog |= genRegMask(REG_GSCOOKIE_TMP_1);
        }

        for (CallArg& arg : call->gtArgs.Args())
        {
            for (unsigned j = 0; j < arg.AbiInfo.NumRegs; j++)
            {
                regNumber reg = arg.AbiInfo.GetRegNum(j);
                if ((trashedByEpilog & genRegMask(reg)) != 0)
                {
                    JITDUMP("Tail call node:\n");
                    DISPTREE(call);
                    JITDUMP("Register used: %s\n", getRegName(reg));
                    assert(!"Argument to tailcall may be trashed by epilog");
                }
            }
        }
    }
#endif // DEBUG
    CORINFO_METHOD_HANDLE methHnd;
    GenTree*              target = getCallTarget(call, &methHnd);

    if (target != nullptr)
    {
        // A call target can not be a contained indirection
        assert(!target->isContainedIndir());

        // For fast tailcall we have already consumed the target. We ensure in
        // RA that the target was allocated into a volatile register that will
        // not be messed up by epilog sequence.
        if (!call->IsFastTailCall())
        {
            genConsumeReg(target);
        }

        // We have already generated code for gtControlExpr evaluating it into a register.
        // We just need to emit "call reg" in this case.
        //
        assert(genIsValidIntReg(target->GetRegNum()));

#ifdef TARGET_ARM64
        bool isTlsHandleTarget =
            compiler->IsTargetAbi(CORINFO_NATIVEAOT_ABI) && TargetOS::IsUnix && target->IsTlsIconHandle();

        if (isTlsHandleTarget)
        {
            assert(call->gtFlags & GTF_TLS_GET_ADDR);
            emitter*       emitter  = GetEmitter();
            emitAttr       attr     = (emitAttr)(EA_CNS_TLSGD_RELOC | EA_CNS_RELOC_FLG | retSize);
            GenTreeIntCon* iconNode = target->AsIntCon();
            methHnd                 = (CORINFO_METHOD_HANDLE)iconNode->gtIconVal;
            retSize                 = EA_SET_FLG(retSize, EA_CNS_TLSGD_RELOC);

            // For NativeAOT, linux/arm64, linker wants the following pattern, so we will generate
            // it as part of the call. Generating individual instructions is tricky to get it
            // correct in the format the way linker needs. Also, we might end up spilling or
            // reloading a register, which can break the pattern.
            //
            //      mrs  x1, tpidr_el0
            //      adrp x0, :tlsdesc:tlsRoot   ; R_AARCH64_TLSDESC_ADR_PAGE21
            //      ldr  x2, [x0]               ; R_AARCH64_TLSDESC_LD64_LO12
            //      add  x0, x0, #0             ; R_AARCH64_TLSDESC_ADD_LO12
            //      blr  x2                     ; R_AARCH64_TLSDESC_CALL
            //      add  x0, x1, x0
            // We guaranteed in LSRA that r0, r1 and r2 are assigned to this node.

            // mrs
            emitter->emitIns_R(INS_mrs_tpid0, attr, REG_R1);

            // adrp
            // ldr
            // add
            emitter->emitIns_Adrp_Ldr_Add(attr, REG_R0, target->GetRegNum(),
                                          (ssize_t)methHnd DEBUGARG(iconNode->gtTargetHandle)
                                              DEBUGARG(iconNode->gtFlags));
        }
#endif

        // clang-format off
        genEmitCall(emitter::EC_INDIR_R,
                    methHnd,
                    INDEBUG_LDISASM_COMMA(sigInfo)
                    nullptr, // addr
                    retSize
                    MULTIREG_HAS_SECOND_GC_RET_ONLY_ARG(secondRetSize),
                    di,
                    target->GetRegNum(),
                    call->IsFastTailCall());

#ifdef TARGET_ARM64
        if (isTlsHandleTarget)
        {
            // add x0, x1, x0
            GetEmitter()->emitIns_R_R_R(INS_add, EA_8BYTE, REG_R0, REG_R1, REG_R0);
        }
#endif
        // clang-format on
    }
    else
    {
        // If we have no target and this is a call with indirection cell then
        // we do an optimization where we load the call address directly from
        // the indirection cell instead of duplicating the tree. In BuildCall
        // we ensure that get an extra register for the purpose. Note that for
        // CFG the call might have changed to
        // CORINFO_HELP_DISPATCH_INDIRECT_CALL in which case we still have the
        // indirection cell but we should not try to optimize.
        regNumber callThroughIndirReg = REG_NA;
        if (!call->IsHelperCall(compiler, CORINFO_HELP_DISPATCH_INDIRECT_CALL))
        {
            callThroughIndirReg = getCallIndirectionCellReg(call);
        }

        if (callThroughIndirReg != REG_NA)
        {
            assert(call->IsR2ROrVirtualStubRelativeIndir());
            regNumber targetAddrReg = call->GetSingleTempReg();
            // For fast tailcalls we have already loaded the call target when processing the call node.
            if (!call->IsFastTailCall())
            {
                GetEmitter()->emitIns_R_R(ins_Load(TYP_I_IMPL), emitActualTypeSize(TYP_I_IMPL), targetAddrReg,
                                          callThroughIndirReg);
            }
            else
            {
                // Register where we save call address in should not be overridden by epilog.
                assert((genRegMask(targetAddrReg) & (RBM_INT_CALLEE_TRASH & ~RBM_LR)) == genRegMask(targetAddrReg));
            }

            // We have now generated code loading the target address from the indirection cell into `targetAddrReg`.
            // We just need to emit "bl targetAddrReg" in this case.
            //
            assert(genIsValidIntReg(targetAddrReg));

            // clang-format off
            genEmitCall(emitter::EC_INDIR_R,
                        methHnd,
                        INDEBUG_LDISASM_COMMA(sigInfo)
                        nullptr, // addr
                        retSize
                        MULTIREG_HAS_SECOND_GC_RET_ONLY_ARG(secondRetSize),
                        di,
                        targetAddrReg,
                        call->IsFastTailCall());
            // clang-format on
        }
        else
        {
            // Generate a direct call to a non-virtual user defined or helper method
            assert(call->IsHelperCall() || (call->gtCallType == CT_USER_FUNC));

            void* addr = nullptr;
#ifdef FEATURE_READYTORUN
            if (call->gtEntryPoint.addr != NULL)
            {
                assert(call->gtEntryPoint.accessType == IAT_VALUE);
                addr = call->gtEntryPoint.addr;
            }
            else
#endif // FEATURE_READYTORUN
                if (call->IsHelperCall())
                {
                    CorInfoHelpFunc helperNum = compiler->eeGetHelperNum(methHnd);
                    noway_assert(helperNum != CORINFO_HELP_UNDEF);

                    void* pAddr = nullptr;
                    addr        = compiler->compGetHelperFtn(helperNum, (void**)&pAddr);
                    assert(pAddr == nullptr);
                }
                else
                {
                    // Direct call to a non-virtual user function.
                    addr = call->gtDirectCallAddress;
                }

            assert(addr != nullptr);

// Non-virtual direct call to known addresses
#ifdef TARGET_ARM
            if (!validImmForBL((ssize_t)addr))
            {
                regNumber tmpReg = call->GetSingleTempReg();
                instGen_Set_Reg_To_Imm(EA_HANDLE_CNS_RELOC, tmpReg, (ssize_t)addr);
                // clang-format off
                genEmitCall(emitter::EC_INDIR_R,
                            methHnd,
                            INDEBUG_LDISASM_COMMA(sigInfo)
                            NULL,
                            retSize,
                            di,
                            tmpReg,
                            call->IsFastTailCall());
                // clang-format on
            }
            else
#endif // TARGET_ARM
            {
                // clang-format off
                genEmitCall(emitter::EC_FUNC_TOKEN,
                            methHnd,
                            INDEBUG_LDISASM_COMMA(sigInfo)
                            addr,
                            retSize
                            MULTIREG_HAS_SECOND_GC_RET_ONLY_ARG(secondRetSize),
                            di,
                            REG_NA,
                            call->IsFastTailCall());
                // clang-format on
            }
        }
    }
}

// Produce code for a GT_JMP node.
// The arguments of the caller needs to be transferred to the callee before exiting caller.
// The actual jump to callee is generated as part of caller epilog sequence.
// Therefore the codegen of GT_JMP is to ensure that the callee arguments are correctly setup.
void CodeGen::genJmpMethod(GenTree* jmp)
{
    assert(jmp->OperGet() == GT_JMP);
    assert(compiler->compJmpOpUsed);

    // If no arguments, nothing to do
    if (compiler->info.compArgsCount == 0)
    {
        return;
    }

    // Make sure register arguments are in their initial registers
    // and stack arguments are put back as well.
    unsigned   varNum;
    LclVarDsc* varDsc;

    // First move any en-registered stack arguments back to the stack.
    // At the same time any reg arg not in correct reg is moved back to its stack location.
    //
    // We are not strictly required to spill reg args that are not in the desired reg for a jmp call
    // But that would require us to deal with circularity while moving values around.  Spilling
    // to stack makes the implementation simple, which is not a bad trade off given Jmp calls
    // are not frequent.
    for (varNum = 0; varNum < compiler->info.compArgsCount; varNum++)
    {
        varDsc = compiler->lvaGetDesc(varNum);

        if (varDsc->lvPromoted)
        {
            noway_assert(varDsc->lvFieldCnt == 1); // We only handle one field here

            unsigned fieldVarNum = varDsc->lvFieldLclStart;
            varDsc               = compiler->lvaGetDesc(fieldVarNum);
        }
        noway_assert(varDsc->lvIsParam);

        if (varDsc->lvIsRegArg && (varDsc->GetRegNum() != REG_STK))
        {
            // Skip reg args which are already in its right register for jmp call.
            // If not, we will spill such args to their stack locations.
            //
            // If we need to generate a tail call profiler hook, then spill all
            // arg regs to free them up for the callback.
            if (!compiler->compIsProfilerHookNeeded() && (varDsc->GetRegNum() == varDsc->GetArgReg()))
                continue;
        }
        else if (varDsc->GetRegNum() == REG_STK)
        {
            // Skip args which are currently living in stack.
            continue;
        }

        // If we came here it means either a reg argument not in the right register or
        // a stack argument currently living in a register.  In either case the following
        // assert should hold.
        assert(varDsc->GetRegNum() != REG_STK);
        assert(varDsc->IsEnregisterableLcl());
        var_types storeType = varDsc->GetStackSlotHomeType();
        emitAttr  storeSize = emitActualTypeSize(storeType);

#ifdef TARGET_ARM
        if (varDsc->TypeGet() == TYP_LONG)
        {
            // long - at least the low half must be enregistered
            GetEmitter()->emitIns_S_R(INS_str, EA_4BYTE, varDsc->GetRegNum(), varNum, 0);

            // Is the upper half also enregistered?
            if (varDsc->GetOtherReg() != REG_STK)
            {
                GetEmitter()->emitIns_S_R(INS_str, EA_4BYTE, varDsc->GetOtherReg(), varNum, sizeof(int));
            }
        }
        else
#endif // TARGET_ARM
        {
            GetEmitter()->emitIns_S_R(ins_Store(storeType), storeSize, varDsc->GetRegNum(), varNum, 0);
        }
        // Update lvRegNum life and GC info to indicate lvRegNum is dead and varDsc stack slot is going live.
        // Note that we cannot modify varDsc->GetRegNum() here because another basic block may not be expecting it.
        // Therefore manually update life of varDsc->GetRegNum().
        regMaskTP tempMask = genRegMask(varDsc->GetRegNum());
        regSet.RemoveMaskVars(tempMask);
        gcInfo.gcMarkRegSetNpt(tempMask);
        if (compiler->lvaIsGCTracked(varDsc))
        {
            VarSetOps::AddElemD(compiler, gcInfo.gcVarPtrSetCur, varNum);
        }
    }

#ifdef PROFILING_SUPPORTED
    // At this point all arg regs are free.
    // Emit tail call profiler callback.
    genProfilingLeaveCallback(CORINFO_HELP_PROF_FCN_TAILCALL);
#endif

    // Next move any un-enregistered register arguments back to their register.
    regMaskTP fixedIntArgMask = RBM_NONE;    // tracks the int arg regs occupying fixed args in case of a vararg method.
    unsigned  firstArgVarNum  = BAD_VAR_NUM; // varNum of the first argument in case of a vararg method.
    for (varNum = 0; varNum < compiler->info.compArgsCount; varNum++)
    {
        varDsc = compiler->lvaGetDesc(varNum);
        if (varDsc->lvPromoted)
        {
            noway_assert(varDsc->lvFieldCnt == 1); // We only handle one field here

            unsigned fieldVarNum = varDsc->lvFieldLclStart;
            varDsc               = compiler->lvaGetDesc(fieldVarNum);
        }
        noway_assert(varDsc->lvIsParam);

        // Skip if arg not passed in a register.
        if (!varDsc->lvIsRegArg)
            continue;

        // Register argument
        noway_assert(isRegParamType(genActualType(varDsc->TypeGet())));

        // Is register argument already in the right register?
        // If not load it from its stack location.
        regNumber argReg     = varDsc->GetArgReg(); // incoming arg register
        regNumber argRegNext = REG_NA;

#ifdef TARGET_ARM64
        if (varDsc->GetRegNum() != argReg)
        {
            var_types loadType = TYP_UNDEF;

            if (varDsc->lvIsHfaRegArg())
            {
                // Note that for HFA, the argument is currently marked address exposed so lvRegNum will always be
                // REG_STK. We home the incoming HFA argument registers in the prolog. Then we'll load them back
                // here, whether they are already in the correct registers or not. This is such a corner case that
                // it is not worth optimizing it.

                assert(!compiler->info.compIsVarArgs);

                loadType           = varDsc->GetHfaType();
                regNumber fieldReg = argReg;
                emitAttr  loadSize = emitActualTypeSize(loadType);
                unsigned  cSlots   = varDsc->lvHfaSlots();

                for (unsigned ofs = 0, cSlot = 0; cSlot < cSlots; cSlot++, ofs += (unsigned)loadSize)
                {
                    GetEmitter()->emitIns_R_S(ins_Load(loadType), loadSize, fieldReg, varNum, ofs);
                    assert(genIsValidFloatReg(fieldReg)); // No GC register tracking for floating point registers.
                    fieldReg = regNextOfType(fieldReg, loadType);
                }
            }
            else
            {
                if (varTypeIsStruct(varDsc))
                {
                    // Must be <= 16 bytes or else it wouldn't be passed in registers, except for HFA,
                    // which can be bigger (and is handled above).
                    noway_assert(EA_SIZE_IN_BYTES(varDsc->lvSize()) <= 16);
                    loadType = varDsc->GetLayout()->GetGCPtrType(0);
                }
                else
                {
                    loadType = compiler->mangleVarArgsType(genActualType(varDsc->TypeGet()));
                }
                emitAttr loadSize = emitActualTypeSize(loadType);
                GetEmitter()->emitIns_R_S(ins_Load(loadType), loadSize, argReg, varNum, 0);

                // Update argReg life and GC Info to indicate varDsc stack slot is dead and argReg is going live.
                // Note that we cannot modify varDsc->GetRegNum() here because another basic block may not be
                // expecting it. Therefore manually update life of argReg.  Note that GT_JMP marks the end of
                // the basic block and after which reg life and gc info will be recomputed for the new block
                // in genCodeForBBList().
                regSet.AddMaskVars(genRegMask(argReg));
                gcInfo.gcMarkRegPtrVal(argReg, loadType);

                if (compiler->lvaIsMultiregStruct(varDsc, compiler->info.compIsVarArgs))
                {
                    // Restore the second register.
                    argRegNext = genRegArgNext(argReg);

                    loadType = varDsc->GetLayout()->GetGCPtrType(1);
                    loadSize = emitActualTypeSize(loadType);
                    GetEmitter()->emitIns_R_S(ins_Load(loadType), loadSize, argRegNext, varNum, TARGET_POINTER_SIZE);

                    regSet.AddMaskVars(genRegMask(argRegNext));
                    gcInfo.gcMarkRegPtrVal(argRegNext, loadType);
                }

                if (compiler->lvaIsGCTracked(varDsc))
                {
                    VarSetOps::RemoveElemD(compiler, gcInfo.gcVarPtrSetCur, varDsc->lvVarIndex);
                }
            }
        }

        if (compiler->info.compIsVarArgs)
        {
            // In case of a jmp call to a vararg method ensure only integer registers are passed.
            assert((genRegMask(argReg) & (RBM_ARG_REGS | RBM_ARG_RET_BUFF)) != RBM_NONE);
            assert(!varDsc->lvIsHfaRegArg());

            fixedIntArgMask |= genRegMask(argReg);

            if (compiler->lvaIsMultiregStruct(varDsc, compiler->info.compIsVarArgs))
            {
                assert(argRegNext != REG_NA);
                fixedIntArgMask |= genRegMask(argRegNext);
            }

            if (argReg == REG_ARG_0)
            {
                assert(firstArgVarNum == BAD_VAR_NUM);
                firstArgVarNum = varNum;
            }
        }

#else  // !TARGET_ARM64

        bool      twoParts = false;
        var_types loadType = TYP_UNDEF;
        if (varDsc->TypeGet() == TYP_LONG)
        {
            twoParts = true;
        }
        else if (varDsc->TypeGet() == TYP_DOUBLE)
        {
            if (compiler->info.compIsVarArgs || compiler->opts.compUseSoftFP)
            {
                twoParts = true;
            }
        }

        if (twoParts)
        {
            argRegNext = genRegArgNext(argReg);

            if (varDsc->GetRegNum() != argReg)
            {
                GetEmitter()->emitIns_R_S(INS_ldr, EA_PTRSIZE, argReg, varNum, 0);
                GetEmitter()->emitIns_R_S(INS_ldr, EA_PTRSIZE, argRegNext, varNum, REGSIZE_BYTES);
            }

            if (compiler->info.compIsVarArgs)
            {
                fixedIntArgMask |= genRegMask(argReg);
                fixedIntArgMask |= genRegMask(argRegNext);
            }
        }
        else if (varDsc->lvIsHfaRegArg())
        {
            loadType           = varDsc->GetHfaType();
            regNumber fieldReg = argReg;
            emitAttr  loadSize = emitActualTypeSize(loadType);
            unsigned  maxSize  = min(varDsc->lvSize(), (LAST_FP_ARGREG + 1 - argReg) * REGSIZE_BYTES);

            for (unsigned ofs = 0; ofs < maxSize; ofs += (unsigned)loadSize)
            {
                if (varDsc->GetRegNum() != argReg)
                {
                    GetEmitter()->emitIns_R_S(ins_Load(loadType), loadSize, fieldReg, varNum, ofs);
                }
                assert(genIsValidFloatReg(fieldReg)); // we don't use register tracking for FP
                fieldReg = regNextOfType(fieldReg, loadType);
            }
        }
        else if (varTypeIsStruct(varDsc))
        {
            regNumber slotReg = argReg;
            unsigned  maxSize = min(varDsc->lvSize(), (REG_ARG_LAST + 1 - argReg) * REGSIZE_BYTES);

            for (unsigned ofs = 0; ofs < maxSize; ofs += REGSIZE_BYTES)
            {
                unsigned idx = ofs / REGSIZE_BYTES;
                loadType     = varDsc->GetLayout()->GetGCPtrType(idx);

                if (varDsc->GetRegNum() != argReg)
                {
                    emitAttr loadSize = emitActualTypeSize(loadType);

                    GetEmitter()->emitIns_R_S(ins_Load(loadType), loadSize, slotReg, varNum, ofs);
                }

                regSet.AddMaskVars(genRegMask(slotReg));
                gcInfo.gcMarkRegPtrVal(slotReg, loadType);
                if (genIsValidIntReg(slotReg) && compiler->info.compIsVarArgs)
                {
                    fixedIntArgMask |= genRegMask(slotReg);
                }

                slotReg = genRegArgNext(slotReg);
            }
        }
        else
        {
            loadType = compiler->mangleVarArgsType(genActualType(varDsc->TypeGet()));

            if (varDsc->GetRegNum() != argReg)
            {
                GetEmitter()->emitIns_R_S(ins_Load(loadType), emitTypeSize(loadType), argReg, varNum, 0);
            }

            regSet.AddMaskVars(genRegMask(argReg));
            gcInfo.gcMarkRegPtrVal(argReg, loadType);

            if (genIsValidIntReg(argReg) && compiler->info.compIsVarArgs)
            {
                fixedIntArgMask |= genRegMask(argReg);
            }
        }

        if (compiler->lvaIsGCTracked(varDsc))
        {
            VarSetOps::RemoveElemD(compiler, gcInfo.gcVarPtrSetCur, varDsc->lvVarIndex);
        }
#endif // !TARGET_ARM64
    }

    // Jmp call to a vararg method - if the method has fewer than fixed arguments that can be max size of reg,
    // load the remaining integer arg registers from the corresponding
    // shadow stack slots.  This is for the reason that we don't know the number and type
    // of non-fixed params passed by the caller, therefore we have to assume the worst case
    // of caller passing all integer arg regs that can be max size of reg.
    //
    // The caller could have passed gc-ref/byref type var args.  Since these are var args
    // the callee no way of knowing their gc-ness.  Therefore, mark the region that loads
    // remaining arg registers from shadow stack slots as non-gc interruptible.
    if (fixedIntArgMask != RBM_NONE)
    {
        assert(compiler->info.compIsVarArgs);
        assert(firstArgVarNum != BAD_VAR_NUM);

        regMaskTP remainingIntArgMask = RBM_ARG_REGS & ~fixedIntArgMask;
        if (remainingIntArgMask != RBM_NONE)
        {
            GetEmitter()->emitDisableGC();
            for (int argNum = 0, argOffset = 0; argNum < MAX_REG_ARG; ++argNum)
            {
                regNumber argReg     = intArgRegs[argNum];
                regMaskTP argRegMask = genRegMask(argReg);

                if ((remainingIntArgMask & argRegMask) != 0)
                {
                    remainingIntArgMask &= ~argRegMask;
                    GetEmitter()->emitIns_R_S(INS_ldr, EA_PTRSIZE, argReg, firstArgVarNum, argOffset);
                }

                argOffset += REGSIZE_BYTES;
            }
            GetEmitter()->emitEnableGC();
        }
    }
}

//------------------------------------------------------------------------
// genIntCastOverflowCheck: Generate overflow checking code for an integer cast.
//
// Arguments:
//    cast - The GT_CAST node
//    desc - The cast description
//    reg  - The register containing the value to check
//
void CodeGen::genIntCastOverflowCheck(GenTreeCast* cast, const GenIntCastDesc& desc, regNumber reg)
{
    switch (desc.CheckKind())
    {
        case GenIntCastDesc::CHECK_POSITIVE:
            GetEmitter()->emitIns_R_I(INS_cmp, EA_ATTR(desc.CheckSrcSize()), reg, 0);
            genJumpToThrowHlpBlk(EJ_lt, SCK_OVERFLOW);
            break;

#ifdef TARGET_64BIT
        case GenIntCastDesc::CHECK_UINT_RANGE:
            // We need to check if the value is not greater than 0xFFFFFFFF but this value
            // cannot be encoded in the immediate operand of CMP. Use TST instead to check
            // if the upper 32 bits are zero.
            GetEmitter()->emitIns_R_I(INS_tst, EA_8BYTE, reg, 0xFFFFFFFF00000000LL);
            genJumpToThrowHlpBlk(EJ_ne, SCK_OVERFLOW);
            break;

        case GenIntCastDesc::CHECK_POSITIVE_INT_RANGE:
            // We need to check if the value is not greater than 0x7FFFFFFF but this value
            // cannot be encoded in the immediate operand of CMP. Use TST instead to check
            // if the upper 33 bits are zero.
            GetEmitter()->emitIns_R_I(INS_tst, EA_8BYTE, reg, 0xFFFFFFFF80000000LL);
            genJumpToThrowHlpBlk(EJ_ne, SCK_OVERFLOW);
            break;

        case GenIntCastDesc::CHECK_INT_RANGE:
        {
            // Emit "if ((long)(int)x != x) goto OVERFLOW"
            GetEmitter()->emitIns_R_R(INS_cmp, EA_8BYTE, reg, reg, INS_OPTS_SXTW);
            genJumpToThrowHlpBlk(EJ_ne, SCK_OVERFLOW);
        }
        break;
#endif

        default:
        {
            assert(desc.CheckKind() == GenIntCastDesc::CHECK_SMALL_INT_RANGE);
            const int castMaxValue = desc.CheckSmallIntMax();
            const int castMinValue = desc.CheckSmallIntMin();

            // Values greater than 255 cannot be encoded in the immediate operand of CMP.
            // Replace (x > max) with (x >= max + 1) where max + 1 (a power of 2) can be
            // encoded. We could do this for all max values but on ARM32 "cmp r0, 255"
            // is better than "cmp r0, 256" because it has a shorter encoding.
            if (castMaxValue > 255)
            {
                assert((castMaxValue == 32767) || (castMaxValue == 65535));
                GetEmitter()->emitIns_R_I(INS_cmp, EA_SIZE(desc.CheckSrcSize()), reg, castMaxValue + 1);
                genJumpToThrowHlpBlk((castMinValue == 0) ? EJ_hs : EJ_ge, SCK_OVERFLOW);
            }
            else
            {
                GetEmitter()->emitIns_R_I(INS_cmp, EA_SIZE(desc.CheckSrcSize()), reg, castMaxValue);
                genJumpToThrowHlpBlk((castMinValue == 0) ? EJ_hi : EJ_gt, SCK_OVERFLOW);
            }

            if (castMinValue != 0)
            {
                GetEmitter()->emitIns_R_I(INS_cmp, EA_SIZE(desc.CheckSrcSize()), reg, castMinValue);
                genJumpToThrowHlpBlk(EJ_lt, SCK_OVERFLOW);
            }
        }
        break;
    }
}

//------------------------------------------------------------------------
// genIntToIntCast: Generate code for an integer cast, with or without overflow check.
//
// Arguments:
//    cast - The GT_CAST node
//
// Assumptions:
//    Neither the source nor target type can be a floating point type.
//
void CodeGen::genIntToIntCast(GenTreeCast* cast)
{
    genConsumeRegs(cast->CastOp());

    GenTree* const  src    = cast->CastOp();
    const regNumber srcReg = src->isUsedFromReg() ? src->GetRegNum() : REG_NA;
    const regNumber dstReg = cast->GetRegNum();
    emitter* const  emit   = GetEmitter();

    assert(genIsValidIntReg(dstReg));

    GenIntCastDesc desc(cast);

    if (desc.CheckKind() != GenIntCastDesc::CHECK_NONE)
    {
        assert(genIsValidIntReg(srcReg));
        genIntCastOverflowCheck(cast, desc, srcReg);
    }

    if ((desc.ExtendKind() != GenIntCastDesc::COPY) || (srcReg != dstReg))
    {
        instruction ins;
        unsigned    insSize;

        switch (desc.ExtendKind())
        {
            case GenIntCastDesc::ZERO_EXTEND_SMALL_INT:
                ins     = (desc.ExtendSrcSize() == 1) ? INS_uxtb : INS_uxth;
                insSize = 4;
                break;
            case GenIntCastDesc::SIGN_EXTEND_SMALL_INT:
                ins     = (desc.ExtendSrcSize() == 1) ? INS_sxtb : INS_sxth;
                insSize = 4;
                break;
#ifdef TARGET_64BIT
            case GenIntCastDesc::ZERO_EXTEND_INT:
                ins     = INS_mov;
                insSize = 4;
                break;
            case GenIntCastDesc::SIGN_EXTEND_INT:
                ins     = INS_sxtw;
                insSize = 8;
                break;
#endif // TARGET_64BIT
            case GenIntCastDesc::COPY:
                ins     = INS_mov;
                insSize = desc.ExtendSrcSize();
                break;
            case GenIntCastDesc::LOAD_ZERO_EXTEND_SMALL_INT:
                ins     = (desc.ExtendSrcSize() == 1) ? INS_ldrb : INS_ldrh;
                insSize = TARGET_POINTER_SIZE;
                break;
            case GenIntCastDesc::LOAD_SIGN_EXTEND_SMALL_INT:
                ins     = (desc.ExtendSrcSize() == 1) ? INS_ldrsb : INS_ldrsh;
                insSize = TARGET_POINTER_SIZE;
                break;
#ifdef TARGET_64BIT
            case GenIntCastDesc::LOAD_ZERO_EXTEND_INT:
                ins     = INS_ldr;
                insSize = 4;
                break;
            case GenIntCastDesc::LOAD_SIGN_EXTEND_INT:
                ins     = INS_ldrsw;
                insSize = 8;
                break;
#endif // TARGET_64BIT
            case GenIntCastDesc::LOAD_SOURCE:
                ins     = ins_Load(src->TypeGet());
                insSize = genTypeSize(genActualType(src));
                break;

            default:
                unreached();
        }

        if (srcReg != REG_NA)
        {
            emit->emitIns_Mov(ins, EA_ATTR(insSize), dstReg, srcReg, /* canSkip */ false);
        }
        else
        {
            // The "used from memory" case. On ArmArch casts are the only nodes which can have
            // contained memory operands, so we have to handle all possible sources "manually".
            assert(src->isUsedFromMemory());

            if (src->isUsedFromSpillTemp())
            {
                assert(src->IsRegOptional());

                TempDsc* tmpDsc = getSpillTempDsc(src);
                unsigned tmpNum = tmpDsc->tdTempNum();
                regSet.tmpRlsTemp(tmpDsc);

                emit->emitIns_R_S(ins, EA_ATTR(insSize), dstReg, tmpNum, 0);
            }
            else if (src->OperIsLocal())
            {
                emit->emitIns_R_S(ins, EA_ATTR(insSize), dstReg, src->AsLclVarCommon()->GetLclNum(),
                                  src->AsLclVarCommon()->GetLclOffs());
            }
            else
            {
                assert(src->OperIs(GT_IND) && !src->AsIndir()->IsVolatile() && !src->AsIndir()->IsUnaligned());
                emit->emitIns_R_R_I(ins, EA_ATTR(insSize), dstReg, src->AsIndir()->Base()->GetRegNum(),
                                    static_cast<int>(src->AsIndir()->Offset()));
            }
        }
    }

    genProduceReg(cast);
}

//------------------------------------------------------------------------
// genFloatToFloatCast: Generate code for a cast between float and double
//
// Arguments:
//    treeNode - The GT_CAST node
//
// Return Value:
//    None.
//
// Assumptions:
//    Cast is a non-overflow conversion.
//    The treeNode must have an assigned register.
//    The cast is between float and double.
//
void CodeGen::genFloatToFloatCast(GenTree* treeNode)
{
    // float <--> double conversions are always non-overflow ones
    assert(treeNode->OperGet() == GT_CAST);
    assert(!treeNode->gtOverflow());

    regNumber targetReg = treeNode->GetRegNum();
    assert(genIsValidFloatReg(targetReg));

    GenTree* op1 = treeNode->AsOp()->gtOp1;
    assert(!op1->isContained());                  // Cannot be contained
    assert(genIsValidFloatReg(op1->GetRegNum())); // Must be a valid float reg.

    var_types dstType = treeNode->CastToType();
    var_types srcType = op1->TypeGet();
    assert(varTypeIsFloating(srcType) && varTypeIsFloating(dstType));

    genConsumeOperands(treeNode->AsOp());

    // treeNode must be a reg
    assert(!treeNode->isContained());

#if defined(TARGET_ARM)

    if (srcType != dstType)
    {
        instruction insVcvt = (srcType == TYP_FLOAT) ? INS_vcvt_f2d  // convert Float to Double
                                                     : INS_vcvt_d2f; // convert Double to Float

        GetEmitter()->emitIns_R_R(insVcvt, emitTypeSize(treeNode), treeNode->GetRegNum(), op1->GetRegNum());
    }
    else
    {
        GetEmitter()->emitIns_Mov(INS_vmov, emitTypeSize(treeNode), treeNode->GetRegNum(), op1->GetRegNum(),
                                  /* canSkip */ true);
    }

#elif defined(TARGET_ARM64)

    if (srcType != dstType)
    {
        insOpts cvtOption = (srcType == TYP_FLOAT) ? INS_OPTS_S_TO_D  // convert Single to Double
                                                   : INS_OPTS_D_TO_S; // convert Double to Single

        GetEmitter()->emitIns_R_R(INS_fcvt, emitActualTypeSize(treeNode), treeNode->GetRegNum(), op1->GetRegNum(),
                                  cvtOption);
    }
    else
    {
        // If double to double cast or float to float cast. Emit a move instruction.
        GetEmitter()->emitIns_Mov(INS_mov, emitActualTypeSize(treeNode), treeNode->GetRegNum(), op1->GetRegNum(),
                                  /* canSkip */ true);
    }

#endif // TARGET*

    genProduceReg(treeNode);
}

//------------------------------------------------------------------------
// genCreateAndStoreGCInfo: Create and record GC Info for the function.
//
void CodeGen::genCreateAndStoreGCInfo(unsigned            codeSize,
                                      unsigned            prologSize,
                                      unsigned epilogSize DEBUGARG(void* codePtr))
{
    IAllocator*    allowZeroAlloc = new (compiler, CMK_GC) CompIAllocator(compiler->getAllocatorGC());
    GcInfoEncoder* gcInfoEncoder  = new (compiler, CMK_GC)
        GcInfoEncoder(compiler->info.compCompHnd, compiler->info.compMethodInfo, allowZeroAlloc, NOMEM);
    assert(gcInfoEncoder != nullptr);

    // Follow the code pattern of the x86 gc info encoder (genCreateAndStoreGCInfoJIT32).
    gcInfo.gcInfoBlockHdrSave(gcInfoEncoder, codeSize, prologSize);

    // We keep the call count for the second call to gcMakeRegPtrTable() below.
    unsigned callCnt = 0;

    // First we figure out the encoder ID's for the stack slots and registers.
    gcInfo.gcMakeRegPtrTable(gcInfoEncoder, codeSize, prologSize, GCInfo::MAKE_REG_PTR_MODE_ASSIGN_SLOTS, &callCnt);

    // Now we've requested all the slots we'll need; "finalize" these (make more compact data structures for them).
    gcInfoEncoder->FinalizeSlotIds();

    // Now we can actually use those slot ID's to declare live ranges.
    gcInfo.gcMakeRegPtrTable(gcInfoEncoder, codeSize, prologSize, GCInfo::MAKE_REG_PTR_MODE_DO_WORK, &callCnt);

#ifdef TARGET_ARM64

    if (compiler->opts.compDbgEnC)
    {
        // what we have to preserve is called the "frame header" (see comments in VM\eetwain.cpp)
        // which is:
        //  -return address (saved lr)
        //  -saved off FP
        //  -all callee-preserved registers in case of varargs
        //  -saved bool for synchronized methods

        int preservedAreaSize = (2 + genCountBits((uint64_t)RBM_ENC_CALLEE_SAVED)) * REGSIZE_BYTES;

        if (compiler->info.compIsVarArgs)
        {
            // Varargs save all int registers between saved registers and PSP.
            preservedAreaSize += MAX_REG_ARG * REGSIZE_BYTES;
        }

        if (compiler->info.compFlags & CORINFO_FLG_SYNCH)
        {
            // bool in synchronized methods that tracks whether the lock has been taken (takes a full pointer sized
            // slot)
            preservedAreaSize += TARGET_POINTER_SIZE;

            // Verify that MonAcquired bool is at the bottom of the frame header
            assert(compiler->lvaGetCallerSPRelativeOffset(compiler->lvaMonAcquired) == -preservedAreaSize);
        }

        // Used to signal both that the method is compiled for EnC, and also the size of the block at the top of the
        // frame
        gcInfoEncoder->SetSizeOfEditAndContinuePreservedArea(preservedAreaSize);
        gcInfoEncoder->SetSizeOfEditAndContinueFixedStackFrame(genTotalFrameSize());

        JITDUMP("EnC info:\n");
        JITDUMP("  EnC preserved area size = %d\n", preservedAreaSize);
        JITDUMP("  Fixed stack frame size = %d\n", genTotalFrameSize());
    }

#endif // TARGET_ARM64

    if (compiler->opts.IsReversePInvoke())
    {
        unsigned reversePInvokeFrameVarNumber = compiler->lvaReversePInvokeFrameVar;
        assert(reversePInvokeFrameVarNumber != BAD_VAR_NUM);
        const LclVarDsc* reversePInvokeFrameVar = compiler->lvaGetDesc(reversePInvokeFrameVarNumber);
        gcInfoEncoder->SetReversePInvokeFrameSlot(reversePInvokeFrameVar->GetStackOffset());
    }

    gcInfoEncoder->Build();

    // GC Encoder automatically puts the GC info in the right spot using ICorJitInfo::allocGCInfo(size_t)
    // let's save the values anyway for debugging purposes
    compiler->compInfoBlkAddr = gcInfoEncoder->Emit();
    compiler->compInfoBlkSize = 0; // not exposed by the GCEncoder interface
}

// clang-format off
const CodeGen::GenConditionDesc CodeGen::GenConditionDesc::map[32]
{
    { },       // NONE
    { },       // 1
    { EJ_lt }, // SLT
    { EJ_le }, // SLE
    { EJ_ge }, // SGE
    { EJ_gt }, // SGT
    { EJ_mi }, // S
    { EJ_pl }, // NS

    { EJ_eq }, // EQ
    { EJ_ne }, // NE
    { EJ_lo }, // ULT
    { EJ_ls }, // ULE
    { EJ_hs }, // UGE
    { EJ_hi }, // UGT
    { EJ_hs }, // C
    { EJ_lo }, // NC

    { EJ_eq },                // FEQ
    { EJ_gt, GT_AND, EJ_lo }, // FNE
    { EJ_lo },                // FLT
    { EJ_ls },                // FLE
    { EJ_ge },                // FGE
    { EJ_gt },                // FGT
    { EJ_vs },                // O
    { EJ_vc },                // NO

    { EJ_eq, GT_OR, EJ_vs },  // FEQU
    { EJ_ne },                // FNEU
    { EJ_lt },                // FLTU
    { EJ_le },                // FLEU
    { EJ_hs },                // FGEU
    { EJ_hi },                // FGTU
    { },                      // P
    { },                      // NP
};
// clang-format on

//------------------------------------------------------------------------
// inst_SETCC: Generate code to set a register to 0 or 1 based on a condition.
//
// Arguments:
//   condition - The condition
//   type      - The type of the value to be produced
//   dstReg    - The destination register to be set to 1 or 0
//
void CodeGen::inst_SETCC(GenCondition condition, var_types type, regNumber dstReg)
{
    assert(varTypeIsIntegral(type));
    assert(genIsValidIntReg(dstReg));

#ifdef TARGET_ARM64
    const GenConditionDesc& desc = GenConditionDesc::Get(condition);

    inst_SET(desc.jumpKind1, dstReg);

    if (desc.oper != GT_NONE)
    {
        BasicBlock* labelNext = genCreateTempLabel();
        inst_JMP((desc.oper == GT_OR) ? desc.jumpKind1 : emitter::emitReverseJumpKind(desc.jumpKind1), labelNext);
        inst_SET(desc.jumpKind2, dstReg);
        genDefineTempLabel(labelNext);
    }
#else
    // Emit code like that:
    //   ...
    //   bgt True
    //   movs rD, #0
    //   b Next
    // True:
    //   movs rD, #1
    // Next:
    //   ...

    BasicBlock* labelTrue = genCreateTempLabel();
    inst_JCC(condition, labelTrue);

    GetEmitter()->emitIns_R_I(INS_mov, emitActualTypeSize(type), dstReg, 0);

    BasicBlock* labelNext = genCreateTempLabel();
    GetEmitter()->emitIns_J(INS_b, labelNext);

    genDefineTempLabel(labelTrue);
    GetEmitter()->emitIns_R_I(INS_mov, emitActualTypeSize(type), dstReg, 1);
    genDefineTempLabel(labelNext);
#endif
}

//------------------------------------------------------------------------
// inst_JMP: Generate a jump instruction.
//
void CodeGen::inst_JMP(emitJumpKind jmp, BasicBlock* tgtBlock)
{
#if !FEATURE_FIXED_OUT_ARGS
    assert((tgtBlock->bbTgtStkDepth * sizeof(int) == genStackLevel) || isFramePointerUsed());
#endif // !FEATURE_FIXED_OUT_ARGS

    GetEmitter()->emitIns_J(emitter::emitJumpKindToIns(jmp), tgtBlock);
}

//------------------------------------------------------------------------
// genCodeForStoreBlk: Produce code for a GT_STORE_BLK node.
//
// Arguments:
//    tree - the node
//
void CodeGen::genCodeForStoreBlk(GenTreeBlk* blkOp)
{
    assert(blkOp->OperIs(GT_STORE_BLK));

    bool isCopyBlk = blkOp->OperIsCopyBlkOp();

    switch (blkOp->gtBlkOpKind)
    {
        case GenTreeBlk::BlkOpKindCpObjUnroll:
            assert(!blkOp->gtBlkOpGcUnsafe);
            genCodeForCpObj(blkOp->AsBlk());
            break;

        case GenTreeBlk::BlkOpKindLoop:
            assert(!isCopyBlk);
            genCodeForInitBlkLoop(blkOp);
            break;

        case GenTreeBlk::BlkOpKindUnroll:
        case GenTreeBlk::BlkOpKindUnrollMemmove:
            if (isCopyBlk)
            {
                if (blkOp->gtBlkOpGcUnsafe)
                {
                    GetEmitter()->emitDisableGC();
                }
                if (blkOp->gtBlkOpKind == GenTreeBlk::BlkOpKindUnroll)
                {
                    genCodeForCpBlkUnroll(blkOp);
                }
                else
                {
                    assert(blkOp->gtBlkOpKind == GenTreeBlk::BlkOpKindUnrollMemmove);
                    genCodeForMemmove(blkOp);
                }
                if (blkOp->gtBlkOpGcUnsafe)
                {
                    GetEmitter()->emitEnableGC();
                }
            }
            else
            {
                assert(!blkOp->gtBlkOpGcUnsafe);
                genCodeForInitBlkUnroll(blkOp);
            }
            break;

        default:
            unreached();
    }
}

//------------------------------------------------------------------------
// genScaledAdd: A helper for genLeaInstruction.
//
void CodeGen::genScaledAdd(emitAttr attr, regNumber targetReg, regNumber baseReg, regNumber indexReg, int scale)
{
    emitter* emit = GetEmitter();
    if (scale == 0)
    {
        // target = base + index
        GetEmitter()->emitIns_R_R_R(INS_add, attr, targetReg, baseReg, indexReg);
    }
    else
    {
// target = base + index<<scale
#if defined(TARGET_ARM)
        emit->emitIns_R_R_R_I(INS_add, attr, targetReg, baseReg, indexReg, scale, INS_FLAGS_DONT_CARE, INS_OPTS_LSL);
#elif defined(TARGET_ARM64)
        emit->emitIns_R_R_R_I(INS_add, attr, targetReg, baseReg, indexReg, scale, INS_OPTS_LSL);
#endif
    }
}

//------------------------------------------------------------------------
// genCodeForMulLong: Generates code for int*int->long multiplication.
//
// Arguments:
//    mul - the GT_MUL_LONG node
//
// Return Value:
//    None.
//
void CodeGen::genCodeForMulLong(GenTreeOp* mul)
{
    assert(mul->OperIs(GT_MUL_LONG));

    genConsumeOperands(mul);

    regNumber   srcReg1 = mul->gtGetOp1()->GetRegNum();
    regNumber   srcReg2 = mul->gtGetOp2()->GetRegNum();
    instruction ins     = mul->IsUnsigned() ? INS_umull : INS_smull;
#ifdef TARGET_ARM
    GetEmitter()->emitIns_R_R_R_R(ins, EA_4BYTE, mul->GetRegNum(), mul->AsMultiRegOp()->gtOtherReg, srcReg1, srcReg2);
#else
    GetEmitter()->emitIns_R_R_R(ins, EA_4BYTE, mul->GetRegNum(), srcReg1, srcReg2);
#endif

    genProduceReg(mul);
}

//------------------------------------------------------------------------
// genLeaInstruction: Produce code for a GT_LEA node.
//
// Arguments:
//    lea - the node
//
void CodeGen::genLeaInstruction(GenTreeAddrMode* lea)
{
    genConsumeOperands(lea);
    emitter* emit   = GetEmitter();
    emitAttr size   = emitTypeSize(lea);
    int      offset = lea->Offset();

    // In ARM we can only load addresses of the form:
    //
    // [Base + index*scale]
    // [Base + Offset]
    // [Literal] (PC-Relative)
    //
    // So for the case of a LEA node of the form [Base + Index*Scale + Offset] we will generate:
    // destReg = baseReg + indexReg * scale;
    // destReg = destReg + offset;
    //
    // TODO-ARM64-CQ: The purpose of the GT_LEA node is to directly reflect a single target architecture
    //             addressing mode instruction.  Currently we're 'cheating' by producing one or more
    //             instructions to generate the addressing mode so we need to modify lowering to
    //             produce LEAs that are a 1:1 relationship to the ARM64 architecture.
    if (lea->HasBase() && lea->HasIndex())
    {
        GenTree* memBase = lea->Base();
        GenTree* index   = lea->Index();

        DWORD scale;

        assert(isPow2(lea->gtScale));
        BitScanForward(&scale, lea->gtScale);

        assert(scale <= 4);

        if (offset != 0)
        {
            regNumber tmpReg = lea->GetSingleTempReg();

            // When generating fully interruptible code we have to use the "large offset" sequence
            // when calculating a EA_BYREF as we can't report a byref that points outside of the object
            //
            bool useLargeOffsetSeq = compiler->GetInterruptible() && (size == EA_BYREF);

            if (!useLargeOffsetSeq && emitter::emitIns_valid_imm_for_add(offset))
            {
                // Generate code to set tmpReg = base + index*scale
                genScaledAdd(size, tmpReg, memBase->GetRegNum(), index->GetRegNum(), scale);

                // Then compute target reg from [tmpReg + offset]
                emit->emitIns_R_R_I(INS_add, size, lea->GetRegNum(), tmpReg, offset);
            }
            else // large offset sequence
            {
                noway_assert(tmpReg != index->GetRegNum());
                noway_assert(tmpReg != memBase->GetRegNum());

                // First load/store tmpReg with the offset constant
                //      rTmp = imm
                instGen_Set_Reg_To_Imm(EA_PTRSIZE, tmpReg, offset);

                // Then add the scaled index register
                //      rTmp = rTmp + index*scale
                genScaledAdd(EA_PTRSIZE, tmpReg, tmpReg, index->GetRegNum(), scale);

                // Then compute target reg from [base + tmpReg ]
                //      rDst = base + rTmp
                emit->emitIns_R_R_R(INS_add, size, lea->GetRegNum(), memBase->GetRegNum(), tmpReg);
            }
        }
        else
        {
#ifdef TARGET_ARM64

            if (index->isContained())
            {
                if (index->OperIs(GT_BFIZ))
                {
                    // Handle LEA with "contained" BFIZ
                    assert(scale == 0);
                    scale = (DWORD)index->gtGetOp2()->AsIntConCommon()->IconValue();
                    index = index->gtGetOp1()->gtGetOp1();
                }
                else if (index->OperIs(GT_CAST))
                {
                    index = index->AsCast()->gtGetOp1();
                }
                else
                {
                    // Only BFIZ/CAST nodes should be present for for contained index on ARM64.
                    // If there are more, we need to handle them here.
                    unreached();
                }
            }
#endif

            // Then compute target reg from [base + index*scale]
            genScaledAdd(size, lea->GetRegNum(), memBase->GetRegNum(), index->GetRegNum(), scale);
        }
    }
    else if (lea->HasBase())
    {
        GenTree* memBase = lea->Base();

        if (emitter::emitIns_valid_imm_for_add(offset))
        {
            if (offset != 0)
            {
                // Then compute target reg from [memBase + offset]
                emit->emitIns_R_R_I(INS_add, size, lea->GetRegNum(), memBase->GetRegNum(), offset);
            }
            else // offset is zero
            {
                emit->emitIns_Mov(INS_mov, size, lea->GetRegNum(), memBase->GetRegNum(), /* canSkip */ true);
            }
        }
        else
        {
            // We require a tmpReg to hold the offset
            regNumber tmpReg = lea->GetSingleTempReg();

            // First load tmpReg with the large offset constant
            instGen_Set_Reg_To_Imm(EA_PTRSIZE, tmpReg, offset);

            // Then compute target reg from [memBase + tmpReg]
            emit->emitIns_R_R_R(INS_add, size, lea->GetRegNum(), memBase->GetRegNum(), tmpReg);
        }
    }
    else if (lea->HasIndex())
    {
        // If we encounter a GT_LEA node without a base it means it came out
        // when attempting to optimize an arbitrary arithmetic expression during lower.
        // This is currently disabled in ARM64 since we need to adjust lower to account
        // for the simpler instructions ARM64 supports.
        // TODO-ARM64-CQ:  Fix this and let LEA optimize arithmetic trees too.
        assert(!"We shouldn't see a baseless address computation during CodeGen for ARM64");
    }

    genProduceReg(lea);
}

#ifdef FEATURE_SIMD
//------------------------------------------------------------------------
// genSIMDSplitReturn: Generates code for returning a fixed-size SIMD type that lives
//                     in a single register, but is returned in multiple registers.
//
// Arguments:
//    src         - The source of the return
//    retTypeDesc - The return type descriptor.
//
void CodeGen::genSIMDSplitReturn(GenTree* src, ReturnTypeDesc* retTypeDesc)
{
    assert(varTypeIsSIMD(src));
    assert(src->isUsedFromReg());
    regNumber srcReg = src->GetRegNum();

    // Treat src register as a homogeneous vector with element size equal to the reg size
    // Insert pieces in order
    unsigned regCount = retTypeDesc->GetReturnRegCount();
    for (unsigned i = 0; i < regCount; ++i)
    {
        var_types type = retTypeDesc->GetReturnRegType(i);
        regNumber reg  = retTypeDesc->GetABIReturnReg(i, compiler->info.compCallConv);
        if (varTypeIsFloating(type))
        {
            // If the register piece is to be passed in a floating point register
            // Use a vector mov element instruction
            // reg is not a vector, so it is in the first element reg[0]
            // mov reg[0], src[i]
            // This effectively moves from `src[i]` to `reg[0]`, upper bits of reg remain unchanged
            // For the case where src == reg, since we are only writing reg[0], as long as we iterate
            // so that src[0] is consumed before writing reg[0], we do not need a temporary.
            GetEmitter()->emitIns_R_R_I_I(INS_mov, emitTypeSize(type), reg, srcReg, 0, i);
        }
        else
        {
            // If the register piece is to be passed in an integer register
            // Use a vector mov to general purpose register instruction
            // mov reg, src[i]
            // This effectively moves from `src[i]` to `reg`
            GetEmitter()->emitIns_R_R_I(INS_mov, emitTypeSize(type), reg, srcReg, i);
        }
    }
}
#endif // FEATURE_SIMD

//------------------------------------------------------------------------
// genPushCalleeSavedRegisters: Push any callee-saved registers we have used.
//
// Arguments (arm64):
//    initReg        - A scratch register (that gets set to zero on some platforms).
//    pInitRegZeroed - OUT parameter. *pInitRegZeroed is set to 'true' if this method sets initReg register to zero,
//                     'false' if initReg was set to a non-zero value, and left unchanged if initReg was not touched.
//
#if defined(TARGET_ARM64)
void CodeGen::genPushCalleeSavedRegisters(regNumber initReg, bool* pInitRegZeroed)
#else
void CodeGen::genPushCalleeSavedRegisters()
#endif
{
    assert(compiler->compGeneratingProlog);

#ifdef TARGET_ARM64
    // Probe large frames now, if necessary, since genPushCalleeSavedRegisters() will allocate the frame. Note that
    // for arm64, genAllocLclFrame only probes the frame; it does not actually allocate it (it does not change SP).
    // For arm64, we are probing the frame before the callee-saved registers are saved. The 'initReg' might have
    // been calculated to be one of the callee-saved registers (say, if all the integer argument registers are
    // in use, and perhaps with other conditions being satisfied). This is ok in other cases, after the callee-saved
    // registers have been saved. So instead of letting genAllocLclFrame use initReg as a temporary register,
    // always use REG_SCRATCH. We don't care if it trashes it, so ignore the initRegZeroed output argument.
    bool ignoreInitRegZeroed = false;
    genAllocLclFrame(compiler->compLclFrameSize, REG_SCRATCH, &ignoreInitRegZeroed,
                     intRegState.rsCalleeRegArgMaskLiveIn);
#endif

    regMaskTP rsPushRegs = regSet.rsGetModifiedCalleeSavedRegsMask();

#if ETW_EBP_FRAMED
    if (!isFramePointerUsed() && regSet.rsRegsModified(RBM_FPBASE))
    {
        noway_assert(!"Used register RBM_FPBASE as a scratch register!");
    }
#endif

    // On ARM we push the FP (frame-pointer) here along with all other callee saved registers
    if (isFramePointerUsed())
        rsPushRegs |= RBM_FPBASE;

    //
    // It may be possible to skip pushing/popping lr for leaf methods. However, such optimization would require
    // changes in GC suspension architecture.
    //
    // We would need to guarantee that a tight loop calling a virtual leaf method can be suspended for GC. Today, we
    // generate partially interruptible code for both the method that contains the tight loop with the call and the leaf
    // method. GC suspension depends on return address hijacking in this case. Return address hijacking depends
    // on the return address to be saved on the stack. If we skipped pushing/popping lr, the return address would never
    // be saved on the stack and the GC suspension would time out.
    //
    // So if we wanted to skip pushing pushing/popping lr for leaf frames, we would also need to do one of
    // the following to make GC suspension work in the above scenario:
    // - Make return address hijacking work even when lr is not saved on the stack.
    // - Generate fully interruptible code for loops that contains calls
    // - Generate fully interruptible code for leaf methods
    //
    // Given the limited benefit from this optimization (<10k for CoreLib NGen image), the extra complexity
    // is not worth it.
    //
    rsPushRegs |= RBM_LR; // We must save the return address (in the LR register)

    regSet.rsMaskCalleeSaved = rsPushRegs;

#ifdef DEBUG
    if (compiler->compCalleeRegsPushed != genCountBits(rsPushRegs))
    {
        printf("Error: unexpected number of callee-saved registers to push. Expected: %d. Got: %d ",
               compiler->compCalleeRegsPushed, genCountBits(rsPushRegs));
        dspRegMask(rsPushRegs);
        printf("\n");
        assert(compiler->compCalleeRegsPushed == genCountBits(rsPushRegs));
    }
#endif // DEBUG

#if defined(TARGET_ARM)
    regMaskTP maskPushRegsFloat = rsPushRegs & RBM_ALLFLOAT;
    regMaskTP maskPushRegsInt   = rsPushRegs & ~maskPushRegsFloat;

    maskPushRegsInt |= genStackAllocRegisterMask(compiler->compLclFrameSize, maskPushRegsFloat);

    assert(FitsIn<int>(maskPushRegsInt));
    inst_IV(INS_push, (int)maskPushRegsInt);
    compiler->unwindPushMaskInt(maskPushRegsInt);

    if (maskPushRegsFloat != 0)
    {
        genPushFltRegs(maskPushRegsFloat);
        compiler->unwindPushMaskFloat(maskPushRegsFloat);
    }
#elif defined(TARGET_ARM64)
    // See the document "ARM64 JIT Frame Layout" and/or "ARM64 Exception Data" for more details or requirements and
    // options. Case numbers in comments here refer to this document. See also Compiler::lvaAssignFrameOffsets()
    // for pictures of the general frame layouts, and CodeGen::genFuncletProlog() implementations (per architecture)
    // for pictures of the funclet frame layouts.
    //
    // For most frames, generate, e.g.:
    //      stp fp,  lr,  [sp,-0x80]!   // predecrement SP with full frame size, and store FP/LR pair.
    //      stp r19, r20, [sp, 0x60]    // store at positive offset from SP established above, into callee-saved area
    //                                  // at top of frame (highest addresses).
    //      stp r21, r22, [sp, 0x70]
    //
    // Notes:
    // 1. We don't always need to save FP. If FP isn't saved, then LR is saved with the other callee-saved registers
    //    at the top of the frame.
    // 2. If we save FP, then the first store is FP, LR.
    // 3. General-purpose registers are 8 bytes, floating-point registers are 16 bytes, but FP/SIMD registers only
    //    preserve their lower 8 bytes, by calling convention.
    // 4. For frames with varargs, we spill the integer register arguments to the stack, so all the arguments are
    //    consecutive, and at the top of the frame.
    // 5. We allocate the frame here; no further changes to SP are allowed (except in the body, for localloc).
    //
    // For functions with GS and localloc, we change the frame so the frame pointer and LR are saved at the top
    // of the frame, just under the varargs registers (if any). Note that the funclet frames must follow the same
    // rule, and both main frame and funclet frames (if any) must put PSPSym in the same offset from Caller-SP.
    // Since this frame type is relatively rare, we force using it via stress modes, for additional coverage.
    //
    // The frames look like the following (simplified to only include components that matter for establishing the
    // frames). See also Compiler::lvaAssignFrameOffsets().
    //
    // Frames with FP, LR saved at bottom of frame (above outgoing argument space):
    //
    //      |                       |
    //      |-----------------------|
    //      |  incoming arguments   |
    //      +=======================+ <---- Caller's SP
    //      |  Varargs regs space   | // Only for varargs functions; 64 bytes
    //      |-----------------------|
    //      |Callee saved registers | // not including FP/LR; multiple of 8 bytes
    //      |-----------------------|
    //      |    MonitorAcquired    | // 8 bytes; for synchronized methods
    //      |-----------------------|
    //      |        PSP slot       | // 8 bytes (omitted in NativeAOT ABI)
    //      |-----------------------|
    //      | locals, temps, etc.   |
    //      |-----------------------|
    //      |  possible GS cookie   |
    //      |-----------------------|
    //      |      Saved LR         | // 8 bytes
    //      |-----------------------|
    //      |      Saved FP         | // 8 bytes
    //      |-----------------------|
    //      |   Outgoing arg space  | // multiple of 8 bytes; if required (i.e., #outsz != 0)
    //      |-----------------------| <---- Ambient SP
    //      |       |               |
    //      ~       | Stack grows   ~
    //      |       | downward      |
    //              V
    //
    // Frames with FP, LR saved at top of frame (below saved varargs incoming arguments):
    //
    //      |                       |
    //      |-----------------------|
    //      |  incoming arguments   |
    //      +=======================+ <---- Caller's SP
    //      |  Varargs regs space   | // Only for varargs functions; 64 bytes
    //      |-----------------------|
    //      |      Saved LR         | // 8 bytes
    //      |-----------------------|
    //      |      Saved FP         | // 8 bytes
    //      |-----------------------|
    //      |Callee saved registers | // not including FP/LR; multiple of 8 bytes
    //      |-----------------------|
    //      |    MonitorAcquired    | // 8 bytes; for synchronized methods
    //      |-----------------------|
    //      |        PSP slot       | // 8 bytes (omitted in NativeAOT ABI)
    //      |-----------------------|
    //      | locals, temps, etc.   |
    //      |-----------------------|
    //      |  possible GS cookie   |
    //      |-----------------------|
    //      |   Outgoing arg space  | // multiple of 8 bytes; if required (i.e., #outsz != 0)
    //      |-----------------------| <---- Ambient SP
    //      |       |               |
    //      ~       | Stack grows   ~
    //      |       | downward      |
    //              V
    //

    int totalFrameSize = genTotalFrameSize();

    int offset; // This will be the starting place for saving the callee-saved registers, in increasing order.

    regMaskTP maskSaveRegsFloat = rsPushRegs & RBM_ALLFLOAT;
    regMaskTP maskSaveRegsInt   = rsPushRegs & ~maskSaveRegsFloat;

#ifdef DEBUG
    if (verbose)
    {
        printf("Save float regs: ");
        dspRegMask(maskSaveRegsFloat);
        printf("\n");
        printf("Save int   regs: ");
        dspRegMask(maskSaveRegsInt);
        printf("\n");
    }
#endif // DEBUG

    // The frameType number is arbitrary, is defined below, and corresponds to one of the frame styles we
    // generate based on various sizes.
    int frameType = 0;

    // The amount to subtract from SP before starting to store the callee-saved registers. It might be folded into the
    // first save instruction as a "predecrement" amount, if possible.
    int calleeSaveSpDelta = 0;

    if (isFramePointerUsed())
    {
        // We need to save both FP and LR.

        assert((maskSaveRegsInt & RBM_FP) != 0);
        assert((maskSaveRegsInt & RBM_LR) != 0);

        // If we need to generate a GS cookie, we need to make sure the saved frame pointer and return address
        // (FP and LR) are protected from buffer overrun by the GS cookie. If FP/LR are at the lowest addresses,
        // then they are safe, since they are lower than any unsafe buffers. And the GS cookie we add will
        // protect our caller's frame. If we have a localloc, however, that is dynamically placed lower than our
        // saved FP/LR. In that case, we save FP/LR along with the rest of the callee-saved registers, above
        // the GS cookie.
        //
        // After the frame is allocated, the frame pointer is established, pointing at the saved frame pointer to
        // create a frame pointer chain.
        //
        // Do we need another frame pointer register to get good code quality in the case of having the frame pointer
        // point high in the frame, so we can take advantage of arm64's preference for positive offsets? C++ native
        // code dedicates callee-saved x19 to this, so generates:
        //      mov x19, sp
        // in the prolog, then uses x19 for local var accesses. Given that this case is so rare, we currently do
        // not do this. That means that negative offsets from FP might need to use the reserved register to form
        // the local variable offset for an addressing mode.

        if (((compiler->lvaOutgoingArgSpaceSize == 0) && (totalFrameSize <= 504)) &&
            !genSaveFpLrWithAllCalleeSavedRegisters)
        {
            // Case #1.
            //
            // Generate:
            //      stp fp,lr,[sp,#-framesz]!
            //
            // The (totalFrameSize <= 504) condition ensures that both the pre-index STP instruction
            // used in the prolog, and the post-index LDP instruction used in the epilog, can be generated.
            // Note that STP and the unwind codes can handle -512, but LDP with a positive post-index value
            // can only handle up to 504, and we want our prolog and epilog to match.
            //
            // After saving callee-saved registers, we establish the frame pointer with:
            //      mov fp,sp
            // We do this *after* saving callee-saved registers, so the prolog/epilog unwind codes mostly match.

            JITDUMP("Frame type 1. #outsz=0; #framesz=%d; LclFrameSize=%d\n", totalFrameSize,
                    compiler->compLclFrameSize);

            frameType = 1;

            assert(totalFrameSize <= STACK_PROBE_BOUNDARY_THRESHOLD_BYTES);

            GetEmitter()->emitIns_R_R_R_I(INS_stp, EA_PTRSIZE, REG_FP, REG_LR, REG_SPBASE, -totalFrameSize,
                                          INS_OPTS_PRE_INDEX);
            compiler->unwindSaveRegPairPreindexed(REG_FP, REG_LR, -totalFrameSize);

            maskSaveRegsInt &= ~(RBM_FP | RBM_LR);                        // We've already saved FP/LR
            offset = (int)compiler->compLclFrameSize + 2 * REGSIZE_BYTES; // 2 for FP/LR
        }
        else if ((totalFrameSize <= 512) && !compiler->opts.compDbgEnC)
        {
            // Case #2.
            //
            // The (totalFrameSize <= 512) condition ensures the callee-saved registers can all be saved using STP
            // with signed offset encoding. The maximum positive STP offset is 504, but when storing a pair of
            // 8 byte registers, the largest actual offset we use would be 512 - 8 * 2 = 496. And STR with positive
            // offset has a range 0 to 32760.
            //
            // After saving callee-saved registers, we establish the frame pointer with:
            //      add fp,sp,#outsz
            // We do this *after* saving callee-saved registers, so the prolog/epilog unwind codes mostly match.

            if (genSaveFpLrWithAllCalleeSavedRegisters)
            {
                JITDUMP("Frame type 4 (save FP/LR at top). #outsz=%d; #framesz=%d; LclFrameSize=%d\n",
                        unsigned(compiler->lvaOutgoingArgSpaceSize), totalFrameSize, compiler->compLclFrameSize);

                frameType = 4;

                // The frame will be allocated below, when the callee-saved registers are saved. This might mean a
                // separate SUB instruction or the SP adjustment might be folded in to the first STP if there is
                // no outgoing argument space AND no local frame space, that is, if the only thing the frame does
                // is save callee-saved registers (and possibly varargs argument registers).
                calleeSaveSpDelta = totalFrameSize;

                offset = (int)compiler->compLclFrameSize;
            }
            else
            {
                JITDUMP("Frame type 2 (save FP/LR at bottom). #outsz=%d; #framesz=%d; LclFrameSize=%d\n",
                        unsigned(compiler->lvaOutgoingArgSpaceSize), totalFrameSize, compiler->compLclFrameSize);

                frameType = 2;

                // Generate:
                //      sub sp,sp,#framesz
                //      stp fp,lr,[sp,#outsz]   // note that by necessity, #outsz <= #framesz - 16, so #outsz <= 496.

                assert(totalFrameSize - compiler->lvaOutgoingArgSpaceSize <= STACK_PROBE_BOUNDARY_THRESHOLD_BYTES);

                GetEmitter()->emitIns_R_R_I(INS_sub, EA_PTRSIZE, REG_SPBASE, REG_SPBASE, totalFrameSize);
                compiler->unwindAllocStack(totalFrameSize);

                assert(compiler->lvaOutgoingArgSpaceSize + 2 * REGSIZE_BYTES <= (unsigned)totalFrameSize);

                GetEmitter()->emitIns_R_R_R_I(INS_stp, EA_PTRSIZE, REG_FP, REG_LR, REG_SPBASE,
                                              compiler->lvaOutgoingArgSpaceSize);
                compiler->unwindSaveRegPair(REG_FP, REG_LR, compiler->lvaOutgoingArgSpaceSize);

                maskSaveRegsInt &= ~(RBM_FP | RBM_LR);                        // We've already saved FP/LR
                offset = (int)compiler->compLclFrameSize + 2 * REGSIZE_BYTES; // 2 for FP/LR
            }
        }
        else
        {
            // Case 5 or 6.
            //
            // First, the callee-saved registers will be saved, and the callee-saved register code must use
            // pre-index to subtract from SP as the first instruction. It must also leave space for varargs
            // registers to be stored. For example:
            //      stp r19,r20,[sp,#-96]!
            //      stp d8,d9,[sp,#16]
            //      ... save varargs incoming integer registers ...
            // Note that all SP alterations must be 16-byte aligned. We have already calculated any alignment to be
            // lower on the stack than the callee-saved registers (see lvaAlignFrame() for how we calculate
            // alignment). So, if there is an odd number of callee-saved registers, we use (for example, with just
            // one saved register):
            //      sub sp,sp,#16
            //      str r19,[sp,#8]
            // This is one additional instruction, but it centralizes the aligned space. Otherwise, it might be
            // possible to have two 8-byte alignment padding words, one below the callee-saved registers, and one
            // above them. If that is preferable, we could implement it.
            //
            // Note that any varargs saved space will always be 16-byte aligned, since there are 8 argument
            // registers.
            //
            // Then, define #remainingFrameSz = #framesz - (callee-saved size + varargs space + possible alignment
            // padding from above). Note that #remainingFrameSz must not be zero, since we still need to save FP,SP.
            //
            // Generate:
            //      sub sp,sp,#remainingFrameSz
            // or, for large frames:
            //      mov rX, #remainingFrameSz // maybe multiple instructions
            //      sub sp,sp,rX
            //
            // followed by:
            //      stp fp,lr,[sp,#outsz]
            //      add fp,sp,#outsz
            //
            // However, we need to handle the case where #outsz is larger than the constant signed offset encoding
            // can handle. And, once again, we might need to deal with #outsz that is not aligned to 16-bytes (i.e.,
            // STACK_ALIGN). So, in the case of large #outsz we will have an additional SP adjustment, using one of
            // the following sequences:
            //
            // Define #remainingFrameSz2 = #remainingFrameSz - #outsz.
            //
            //      sub sp,sp,#remainingFrameSz2  // if #remainingFrameSz2 is 16-byte aligned
            //      stp fp,lr,[sp]
            //      mov fp,sp
            //      sub sp,sp,#outsz    // in this case, #outsz must also be 16-byte aligned
            //
            // Or:
            //
            //      sub sp,sp,roundUp(#remainingFrameSz2,16) // if #remainingFrameSz2 is not 16-byte aligned (it is
            //                                               // always guaranteed to be 8 byte aligned).
            //      stp fp,lr,[sp,#8]                        // it will always be #8 in the unaligned case
            //      add fp,sp,#8
            //      sub sp,sp,#outsz - #8
            //
            // (As usual, for a large constant "#outsz - #8", we might need multiple instructions:
            //      mov rX, #outsz - #8 // maybe multiple instructions
            //      sub sp,sp,rX
            // )
            //
            // Note that even if we align the SP alterations, that does not imply that we are creating empty alignment
            // slots. In fact, we are not; any empty alignment slots were calculated in
            // Compiler::lvaAssignFrameOffsets() and its callees.

            int calleeSaveSpDeltaUnaligned = totalFrameSize - compiler->compLclFrameSize;
            if (genSaveFpLrWithAllCalleeSavedRegisters)
            {
                JITDUMP("Frame type 5 (save FP/LR at top). #outsz=%d; #framesz=%d; LclFrameSize=%d\n",
                        unsigned(compiler->lvaOutgoingArgSpaceSize), totalFrameSize, compiler->compLclFrameSize);

                // This case is much simpler, because we allocate space for the callee-saved register area, including
                // FP/LR. Note the SP adjustment might be SUB or be folded into the first store as a predecrement.
                // Then, we use a single SUB to establish the rest of the frame. We need to be careful about where
                // to establish the frame pointer, as there is a limit of 2040 bytes offset from SP to FP in the
                // unwind codes when FP is established.
                frameType = 5;
            }
            else
            {
                assert(!compiler->opts.compDbgEnC);
                JITDUMP("Frame type 3 (save FP/LR at bottom). #outsz=%d; #framesz=%d; LclFrameSize=%d\n",
                        unsigned(compiler->lvaOutgoingArgSpaceSize), totalFrameSize, compiler->compLclFrameSize);

                frameType = 3;

                calleeSaveSpDeltaUnaligned -= 2 * REGSIZE_BYTES; // 2 for FP, LR which we'll save later.

                // We'll take care of these later, but callee-saved regs code shouldn't see them.
                maskSaveRegsInt &= ~(RBM_FP | RBM_LR);
            }

            assert(calleeSaveSpDeltaUnaligned >= 0);
            assert((calleeSaveSpDeltaUnaligned % 8) == 0); // It better at least be 8 byte aligned.
            calleeSaveSpDelta = AlignUp((UINT)calleeSaveSpDeltaUnaligned, STACK_ALIGN);

            offset = calleeSaveSpDelta - calleeSaveSpDeltaUnaligned;

            JITDUMP("    calleeSaveSpDelta=%d, offset=%d\n", calleeSaveSpDelta, offset);

            // At most one alignment slot between SP and where we store the callee-saved registers.
            assert((offset == 0) || (offset == REGSIZE_BYTES));
        }
    }
    else
    {
        // No frame pointer (no chaining).
        assert((maskSaveRegsInt & RBM_FP) == 0);
        assert((maskSaveRegsInt & RBM_LR) != 0);

        // Note that there is no pre-indexed save_lrpair unwind code variant, so we can't allocate the frame using
        // 'stp' if we only have one callee-saved register plus LR to save.

        NYI("Frame without frame pointer");
        offset = 0;
    }

    assert(frameType != 0);

    const int calleeSaveSpOffset = offset;

    JITDUMP("    offset=%d, calleeSaveSpDelta=%d\n", offset, calleeSaveSpDelta);
    genSaveCalleeSavedRegistersHelp(maskSaveRegsInt | maskSaveRegsFloat, offset, -calleeSaveSpDelta);

    offset += genCountBits(maskSaveRegsInt | maskSaveRegsFloat) * REGSIZE_BYTES;

    // For varargs, home the incoming arg registers last. Note that there is nothing to unwind here,
    // so we just report "NOP" unwind codes. If there's no more frame setup after this, we don't
    // need to add codes at all.

    if (compiler->info.compIsVarArgs)
    {
        JITDUMP("    compIsVarArgs=true\n");

        // There are 8 general-purpose registers to home, thus 'offset' must be 16-byte aligned here.
        assert((offset % 16) == 0);
        for (regNumber reg1 = REG_ARG_FIRST; reg1 < REG_ARG_LAST; reg1 = REG_NEXT(REG_NEXT(reg1)))
        {
            regNumber reg2 = REG_NEXT(reg1);
            // stp REG, REG + 1, [SP, #offset]
            GetEmitter()->emitIns_R_R_R_I(INS_stp, EA_PTRSIZE, reg1, reg2, REG_SPBASE, offset);
            compiler->unwindNop();
            offset += 2 * REGSIZE_BYTES;
        }
    }

    // By default, we'll establish the frame pointer chain. (Note that currently frames without FP are NYI.)
    bool establishFramePointer = true;

    // If we do establish the frame pointer, what is the amount we add to SP to do so?
    unsigned offsetSpToSavedFp = 0;

    if (frameType == 1)
    {
        assert(!genSaveFpLrWithAllCalleeSavedRegisters);
        assert(offsetSpToSavedFp == 0);
    }
    else if (frameType == 2)
    {
        assert(!genSaveFpLrWithAllCalleeSavedRegisters);

        offsetSpToSavedFp = compiler->lvaOutgoingArgSpaceSize;
    }
    else if (frameType == 3)
    {
        assert(!genSaveFpLrWithAllCalleeSavedRegisters);

        int remainingFrameSz = totalFrameSize - calleeSaveSpDelta;
        assert(remainingFrameSz > 0);
        assert((remainingFrameSz % 16) == 0); // this is guaranteed to be 16-byte aligned because each component --
                                              // totalFrameSize and calleeSaveSpDelta -- is 16-byte aligned.

        if (compiler->lvaOutgoingArgSpaceSize > 504)
        {
            // We can't do "stp fp,lr,[sp,#outsz]" because #outsz is too big.
            // If compiler->lvaOutgoingArgSpaceSize is not aligned, we need to align the SP adjustment.
            assert(remainingFrameSz > (int)compiler->lvaOutgoingArgSpaceSize);
            int spAdjustment2Unaligned = remainingFrameSz - compiler->lvaOutgoingArgSpaceSize;
            int spAdjustment2          = (int)roundUp((unsigned)spAdjustment2Unaligned, STACK_ALIGN);
            int alignmentAdjustment2   = spAdjustment2 - spAdjustment2Unaligned;
            assert((alignmentAdjustment2 == 0) || (alignmentAdjustment2 == 8));

            JITDUMP("    spAdjustment2=%d\n", spAdjustment2);

            genPrologSaveRegPair(REG_FP, REG_LR, alignmentAdjustment2, -spAdjustment2, false, initReg, pInitRegZeroed);
            offset += spAdjustment2;

            // Now subtract off the #outsz (or the rest of the #outsz if it was unaligned, and the above "sub"
            // included some of it)

            int spAdjustment3 = compiler->lvaOutgoingArgSpaceSize - alignmentAdjustment2;
            assert(spAdjustment3 > 0);
            assert((spAdjustment3 % 16) == 0);

            JITDUMP("    alignmentAdjustment2=%d\n", alignmentAdjustment2);
            genEstablishFramePointer(alignmentAdjustment2, /* reportUnwindData */ true);

            // We just established the frame pointer chain; don't do it again.
            establishFramePointer = false;

            JITDUMP("    spAdjustment3=%d\n", spAdjustment3);

            // We've already established the frame pointer, so no need to report the stack pointer change to unwind
            // info.
            genStackPointerAdjustment(-spAdjustment3, initReg, pInitRegZeroed, /* reportUnwindData */ false);
            offset += spAdjustment3;
        }
        else
        {
            genPrologSaveRegPair(REG_FP, REG_LR, compiler->lvaOutgoingArgSpaceSize, -remainingFrameSz, false, initReg,
                                 pInitRegZeroed);
            offset += remainingFrameSz;

            offsetSpToSavedFp = compiler->lvaOutgoingArgSpaceSize;
        }
    }
    else if (frameType == 4)
    {
        assert(genSaveFpLrWithAllCalleeSavedRegisters);
        offsetSpToSavedFp = calleeSaveSpDelta - (compiler->info.compIsVarArgs ? MAX_REG_ARG * REGSIZE_BYTES : 0) -
                            2 * REGSIZE_BYTES; // -2 for FP, LR
    }
    else if (frameType == 5)
    {
        assert(genSaveFpLrWithAllCalleeSavedRegisters);

        offsetSpToSavedFp = calleeSaveSpDelta - (compiler->info.compIsVarArgs ? MAX_REG_ARG * REGSIZE_BYTES : 0) -
                            2 * REGSIZE_BYTES; // -2 for FP, LR
        JITDUMP("    offsetSpToSavedFp=%d\n", offsetSpToSavedFp);
        genEstablishFramePointer(offsetSpToSavedFp, /* reportUnwindData */ true);

        // We just established the frame pointer chain; don't do it again.
        establishFramePointer = false;

        int remainingFrameSz = totalFrameSize - calleeSaveSpDelta;
        if (remainingFrameSz > 0)
        {
            assert((remainingFrameSz % 16) == 0); // this is guaranteed to be 16-byte aligned because each component --
                                                  // totalFrameSize and calleeSaveSpDelta -- is 16-byte aligned.

            JITDUMP("    remainingFrameSz=%d\n", remainingFrameSz);

            // We've already established the frame pointer, so no need to report the stack pointer change to unwind
            // info.
            genStackPointerAdjustment(-remainingFrameSz, initReg, pInitRegZeroed, /* reportUnwindData */ false);
            offset += remainingFrameSz;
        }
        else
        {
            // Should only have picked this frame type for EnC.
            assert(compiler->opts.compDbgEnC);
        }
    }
    else
    {
        unreached();
    }

    if (establishFramePointer)
    {
        JITDUMP("    offsetSpToSavedFp=%d\n", offsetSpToSavedFp);
        genEstablishFramePointer(offsetSpToSavedFp, /* reportUnwindData */ true);
    }

    assert(offset == totalFrameSize);

    // Save off information about the frame for later use
    //
    compiler->compFrameInfo.frameType          = frameType;
    compiler->compFrameInfo.calleeSaveSpOffset = calleeSaveSpOffset;
    compiler->compFrameInfo.calleeSaveSpDelta  = calleeSaveSpDelta;
    compiler->compFrameInfo.offsetSpToSavedFp  = offsetSpToSavedFp;
#endif // TARGET_ARM64
}

/*****************************************************************************
 *
 *  Generates code for a function epilog.
 *
 *  Please consult the "debugger team notification" comment in genFnProlog().
 */

void CodeGen::genFnEpilog(BasicBlock* block)
{
#ifdef DEBUG
    if (verbose)
        printf("*************** In genFnEpilog()\n");
#endif // DEBUG

    ScopedSetVariable<bool> _setGeneratingEpilog(&compiler->compGeneratingEpilog, true);

    VarSetOps::Assign(compiler, gcInfo.gcVarPtrSetCur, GetEmitter()->emitInitGCrefVars);
    gcInfo.gcRegGCrefSetCur = GetEmitter()->emitInitGCrefRegs;
    gcInfo.gcRegByrefSetCur = GetEmitter()->emitInitByrefRegs;

#ifdef DEBUG
    if (compiler->opts.dspCode)
        printf("\n__epilog:\n");

    if (verbose)
    {
        printf("gcVarPtrSetCur=%s ", VarSetOps::ToString(compiler, gcInfo.gcVarPtrSetCur));
        dumpConvertedVarSet(compiler, gcInfo.gcVarPtrSetCur);
        printf(", gcRegGCrefSetCur=");
        printRegMaskInt(gcInfo.gcRegGCrefSetCur);
        GetEmitter()->emitDispRegSet(gcInfo.gcRegGCrefSetCur);
        printf(", gcRegByrefSetCur=");
        printRegMaskInt(gcInfo.gcRegByrefSetCur);
        GetEmitter()->emitDispRegSet(gcInfo.gcRegByrefSetCur);
        printf("\n");
    }
#endif // DEBUG

    bool jmpEpilog = block->HasFlag(BBF_HAS_JMP);

    GenTree* lastNode = block->lastNode();

    // Method handle and address info used in case of jump epilog
    CORINFO_METHOD_HANDLE methHnd = nullptr;
    CORINFO_CONST_LOOKUP  addrInfo;
    addrInfo.addr       = nullptr;
    addrInfo.accessType = IAT_VALUE;

    if (jmpEpilog && lastNode->gtOper == GT_JMP)
    {
        methHnd = (CORINFO_METHOD_HANDLE)lastNode->AsVal()->gtVal1;
        compiler->info.compCompHnd->getFunctionEntryPoint(methHnd, &addrInfo);
    }

#ifdef TARGET_ARM
    // We delay starting the unwind codes until we have an instruction which we know
    // needs an unwind code. In particular, for large stack frames in methods without
    // localloc, the sequence might look something like this:
    //      movw    r3, 0x38e0
    //      add     sp, r3
    //      pop     {r4,r5,r6,r10,r11,pc}
    // In this case, the "movw" should not be part of the unwind codes, since it will
    // be a NOP, and it is a waste to start with a NOP. Note that calling unwindBegEpilog()
    // also sets the current location as the beginning offset of the epilog, so every
    // instruction afterwards needs an unwind code. In the case above, if you call
    // unwindBegEpilog() before the "movw", then you must generate a NOP for the "movw".

    bool unwindStarted = false;

    // Tear down the stack frame

    if (compiler->compLocallocUsed)
    {
        if (!unwindStarted)
        {
            compiler->unwindBegEpilog();
            unwindStarted = true;
        }

        // mov R9 into SP
        inst_Mov(TYP_I_IMPL, REG_SP, REG_SAVED_LOCALLOC_SP, /* canSkip */ false);
        compiler->unwindSetFrameReg(REG_SAVED_LOCALLOC_SP, 0);
    }

    if (jmpEpilog ||
        genStackAllocRegisterMask(compiler->compLclFrameSize, regSet.rsGetModifiedFltCalleeSavedRegsMask()) == RBM_NONE)
    {
        genFreeLclFrame(compiler->compLclFrameSize, &unwindStarted);
    }

    if (!unwindStarted)
    {
        // If we haven't generated anything yet, we're certainly going to generate a "pop" next.
        compiler->unwindBegEpilog();
        unwindStarted = true;
    }

    if (jmpEpilog && lastNode->gtOper == GT_JMP && addrInfo.accessType == IAT_RELPVALUE)
    {
        // IAT_RELPVALUE jump at the end is done using relative indirection, so,
        // additional helper register is required.
        // We use LR just before it is going to be restored from stack, i.e.
        //
        //     movw r12, laddr
        //     movt r12, haddr
        //     mov lr, r12
        //     ldr r12, [r12]
        //     add r12, r12, lr
        //     pop {lr}
        //     ...
        //     bx r12

        regNumber indCallReg = REG_R12;
        regNumber vptrReg1   = REG_LR;

        instGen_Set_Reg_To_Imm(EA_HANDLE_CNS_RELOC, indCallReg, (ssize_t)addrInfo.addr);
        GetEmitter()->emitIns_Mov(INS_mov, EA_PTRSIZE, vptrReg1, indCallReg, /* canSkip */ false);
        GetEmitter()->emitIns_R_R_I(INS_ldr, EA_PTRSIZE, indCallReg, indCallReg, 0);
        GetEmitter()->emitIns_R_R(INS_add, EA_PTRSIZE, indCallReg, vptrReg1);
    }

    genPopCalleeSavedRegisters(jmpEpilog);

    if (regSet.rsMaskPreSpillRegs(true) != RBM_NONE)
    {
        // We better not have used a pop PC to return otherwise this will be unreachable code
        noway_assert(!genUsedPopToReturn);

        int preSpillRegArgSize = genCountBits(regSet.rsMaskPreSpillRegs(true)) * REGSIZE_BYTES;
        inst_RV_IV(INS_add, REG_SPBASE, preSpillRegArgSize, EA_PTRSIZE);
        compiler->unwindAllocStack(preSpillRegArgSize);
    }

    if (jmpEpilog)
    {
        // We better not have used a pop PC to return otherwise this will be unreachable code
        noway_assert(!genUsedPopToReturn);
    }

#else  // TARGET_ARM64
    compiler->unwindBegEpilog();

    genPopCalleeSavedRegistersAndFreeLclFrame(jmpEpilog);
#endif // TARGET_ARM64

    if (jmpEpilog)
    {
        SetHasTailCalls(true);

        noway_assert(block->KindIs(BBJ_RETURN));
        noway_assert(block->GetFirstLIRNode() != nullptr);

        /* figure out what jump we have */
        GenTree* jmpNode = lastNode;
#if !FEATURE_FASTTAILCALL
        noway_assert(jmpNode->gtOper == GT_JMP);
#else  // FEATURE_FASTTAILCALL
       // armarch
       // If jmpNode is GT_JMP then gtNext must be null.
       // If jmpNode is a fast tail call, gtNext need not be null since it could have embedded stmts.
        noway_assert((jmpNode->gtOper != GT_JMP) || (jmpNode->gtNext == nullptr));

        // Could either be a "jmp method" or "fast tail call" implemented as epilog+jmp
        noway_assert((jmpNode->gtOper == GT_JMP) ||
                     ((jmpNode->gtOper == GT_CALL) && jmpNode->AsCall()->IsFastTailCall()));

        // The next block is associated with this "if" stmt
        if (jmpNode->gtOper == GT_JMP)
#endif // FEATURE_FASTTAILCALL
        {
            // Simply emit a jump to the methodHnd. This is similar to a call so we can use
            // the same descriptor with some minor adjustments.
            assert(methHnd != nullptr);
            assert(addrInfo.addr != nullptr);

#ifdef TARGET_ARMARCH
            emitter::EmitCallType callType;
            void*                 addr;
            regNumber             indCallReg;
            switch (addrInfo.accessType)
            {
                case IAT_VALUE:
                    if (validImmForBL((ssize_t)addrInfo.addr))
                    {
                        // Simple direct call
                        callType   = emitter::EC_FUNC_TOKEN;
                        addr       = addrInfo.addr;
                        indCallReg = REG_NA;
                        break;
                    }

                    // otherwise the target address doesn't fit in an immediate
                    // so we have to burn a register...
                    FALLTHROUGH;

                case IAT_PVALUE:
                    // Load the address into a register, load indirect and call  through a register
                    // We have to use R12 since we assume the argument registers are in use
                    callType   = emitter::EC_INDIR_R;
                    indCallReg = REG_INDIRECT_CALL_TARGET_REG;
                    addr       = NULL;
                    instGen_Set_Reg_To_Imm(EA_HANDLE_CNS_RELOC, indCallReg, (ssize_t)addrInfo.addr);
                    if (addrInfo.accessType == IAT_PVALUE)
                    {
                        GetEmitter()->emitIns_R_R_I(INS_ldr, EA_PTRSIZE, indCallReg, indCallReg, 0);
                        regSet.verifyRegUsed(indCallReg);
                    }
                    break;

                case IAT_RELPVALUE:
                {
                    // Load the address into a register, load relative indirect and call through a register
                    // We have to use R12 since we assume the argument registers are in use
                    // LR is used as helper register right before it is restored from stack, thus,
                    // all relative address calculations are performed before LR is restored.
                    callType   = emitter::EC_INDIR_R;
                    indCallReg = REG_R12;
                    addr       = NULL;

                    regSet.verifyRegUsed(indCallReg);
                    break;
                }

                case IAT_PPVALUE:
                default:
                    NO_WAY("Unsupported JMP indirection");
            }

            /* Simply emit a jump to the methodHnd. This is similar to a call so we can use
             * the same descriptor with some minor adjustments.
             */

            // clang-format off
            GetEmitter()->emitIns_Call(callType,
                                       methHnd,
                                       INDEBUG_LDISASM_COMMA(nullptr)
                                       addr,
                                       0,          // argSize
                                       EA_UNKNOWN, // retSize
#if defined(TARGET_ARM64)
                                       EA_UNKNOWN, // secondRetSize
#endif
                                       gcInfo.gcVarPtrSetCur,
                                       gcInfo.gcRegGCrefSetCur,
                                       gcInfo.gcRegByrefSetCur,
                                       DebugInfo(),
                                       indCallReg,    // ireg
                                       REG_NA,        // xreg
                                       0,             // xmul
                                       0,             // disp
                                       true);         // isJump
            // clang-format on
#endif // TARGET_ARMARCH
        }
#if FEATURE_FASTTAILCALL
        else
        {
            genCallInstruction(jmpNode->AsCall());
        }
#endif // FEATURE_FASTTAILCALL
    }
    else
    {
#ifdef TARGET_ARM
        if (!genUsedPopToReturn)
        {
            // If we did not use a pop to return, then we did a "pop {..., lr}" instead of "pop {..., pc}",
            // so we need a "bx lr" instruction to return from the function.
            inst_RV(INS_bx, REG_LR, TYP_I_IMPL);
            compiler->unwindBranch16();
        }
#else  // TARGET_ARM64
        inst_RV(INS_ret, REG_LR, TYP_I_IMPL);
        compiler->unwindReturn(REG_LR);
#endif // TARGET_ARM64
    }

    compiler->unwindEndEpilog();
}
#endif // TARGET_ARMARCH