[RISCV][GISel] Add ISel support for SHXADD_UW and SLLI.UW

llvm/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp

@@ -76,6 +76,13 @@ class RISCVInstructionSelector : public InstructionSelector {
     return selectSHXADDOp(Root, ShAmt);
   }
 
+  ComplexRendererFns selectSHXADD_UWOp(MachineOperand &Root,
+                                       unsigned ShAmt) const;
+  template <unsigned ShAmt>
+  ComplexRendererFns selectSHXADD_UWOp(MachineOperand &Root) const {
+    return selectSHXADD_UWOp(Root, ShAmt);
+  }
+
   // Custom renderers for tablegen
   void renderNegImm(MachineInstrBuilder &MIB, const MachineInstr &MI,
                     int OpIdx) const;
@@ -91,6 +98,9 @@ class RISCVInstructionSelector : public InstructionSelector {
                                 MachineRegisterInfo &MRI, RISCVCC::CondCode &CC,
                                 Register &LHS, Register &RHS) const;
 
+  void renderTrailingZeros(MachineInstrBuilder &MIB, const MachineInstr &MI,
+                           int OpIdx) const;
+
   const RISCVSubtarget &STI;
   const RISCVInstrInfo &TII;
   const RISCVRegisterInfo &TRI;
@@ -239,6 +249,47 @@ RISCVInstructionSelector::selectSHXADDOp(MachineOperand &Root,
   return std::nullopt;
 }
 
+InstructionSelector::ComplexRendererFns
+RISCVInstructionSelector::selectSHXADD_UWOp(MachineOperand &Root,
+                                            unsigned ShAmt) const {
+  using namespace llvm::MIPatternMatch;
+  MachineFunction &MF = *Root.getParent()->getParent()->getParent();
+  MachineRegisterInfo &MRI = MF.getRegInfo();
+
+  if (!Root.isReg())
+    return std::nullopt;
+  Register RootReg = Root.getReg();
+
+  // Given (and (shl x, c2), mask) in which mask is a shifted mask with
+  // 32 - ShAmt leading zeros and c2 trailing zeros. We can use SLLI by
+  // c2 - ShAmt followed by SHXADD_UW with ShAmt for x amount.
+  APInt Mask, C2;
+  Register RegX;
+  if (mi_match(
+          RootReg, MRI,
+          m_OneNonDBGUse(m_GAnd(m_OneNonDBGUse(m_GShl(m_Reg(RegX), m_ICst(C2))),
+                                m_ICst(Mask))))) {
+    Mask &= maskTrailingZeros<uint64_t>(C2.getLimitedValue());
+
+    if (Mask.isShiftedMask()) {
+      unsigned Leading = Mask.countl_zero();
+      unsigned Trailing = Mask.countr_zero();
+      if (Leading == 32 - ShAmt && C2 == Trailing && Trailing > ShAmt) {
+        Register DstReg =
+            MRI.createGenericVirtualRegister(MRI.getType(RootReg));
+        return {{[=](MachineInstrBuilder &MIB) {
+          MachineIRBuilder(*MIB.getInstr())
+              .buildInstr(RISCV::SLLI, {DstReg}, {RegX})
+              .addImm(C2.getLimitedValue() - ShAmt);
+          MIB.addReg(DstReg);
+        }}};
+      }
+    }
+  }
+
+  return std::nullopt;
+}
+
 InstructionSelector::ComplexRendererFns
 RISCVInstructionSelector::selectAddrRegImm(MachineOperand &Root) const {
   // TODO: Need to get the immediate from a G_PTR_ADD. Should this be done in
@@ -383,6 +434,15 @@ void RISCVInstructionSelector::renderImm(MachineInstrBuilder &MIB,
   MIB.addImm(CstVal);
 }
 
+void RISCVInstructionSelector::renderTrailingZeros(MachineInstrBuilder &MIB,
+                                                   const MachineInstr &MI,
+                                                   int OpIdx) const {
+  assert(MI.getOpcode() == TargetOpcode::G_CONSTANT && OpIdx == -1 &&
+         "Expected G_CONSTANT");
+  uint64_t C = MI.getOperand(1).getCImm()->getZExtValue();
+  MIB.addImm(llvm::countr_zero(C));
+}
+
 const TargetRegisterClass *RISCVInstructionSelector::getRegClassForTypeOnBank(
     LLT Ty, const RegisterBank &RB) const {
   if (RB.getID() == RISCV::GPRRegBankID) {

llvm/lib/Target/RISCV/RISCVGISel.td

@@ -57,6 +57,9 @@ def as_i64imm : SDNodeXForm<imm, [{
 def gi_as_i64imm : GICustomOperandRenderer<"renderImm">,
   GISDNodeXFormEquiv<as_i64imm>;
 
+def gi_trailing_zero : GICustomOperandRenderer<"renderTrailingZeros">,
+  GISDNodeXFormEquiv<TrailingZeros>;
+
 // FIXME: This is labelled as handling 's32', however the ComplexPattern it
 // refers to handles both i32 and i64 based on the HwMode. Currently this LLT
 // parameter appears to be ignored so this pattern works for both, however we
@@ -73,6 +76,13 @@ def gi_sh2add_op : GIComplexOperandMatcher<s32, "selectSHXADDOp<2>">,
 def gi_sh3add_op : GIComplexOperandMatcher<s32, "selectSHXADDOp<3>">,
                    GIComplexPatternEquiv<sh3add_op>;
 
+def gi_sh1add_uw_op : GIComplexOperandMatcher<s32, "selectSHXADD_UWOp<1>">,
+                      GIComplexPatternEquiv<sh1add_uw_op>;
+def gi_sh2add_uw_op : GIComplexOperandMatcher<s32, "selectSHXADD_UWOp<2>">,
+                      GIComplexPatternEquiv<sh2add_uw_op>;
+def gi_sh3add_uw_op : GIComplexOperandMatcher<s32, "selectSHXADD_UWOp<3>">,
+                      GIComplexPatternEquiv<sh3add_uw_op>;
+
 // FIXME: Canonicalize (sub X, C) -> (add X, -C) earlier.
 def : Pat<(XLenVT (sub GPR:$rs1, simm12Plus1:$imm)),
           (ADDI GPR:$rs1, (NegImm simm12Plus1:$imm))>;

llvm/lib/Target/RISCV/RISCVInstrInfoXTHead.td

@@ -540,11 +540,11 @@ def : Pat<(add (XLenVT GPR:$rs1), (shl GPR:$rs2, uimm2:$uimm2)),
           (TH_ADDSL GPR:$rs1, GPR:$rs2, uimm2:$uimm2)>;
 
 // Reuse complex patterns from StdExtZba
-def : Pat<(add sh1add_op:$rs1, non_imm12:$rs2),
+def : Pat<(add_non_imm12 sh1add_op:$rs1, (XLenVT GPR:$rs2)),
           (TH_ADDSL GPR:$rs2, sh1add_op:$rs1, 1)>;
-def : Pat<(add sh2add_op:$rs1, non_imm12:$rs2),
+def : Pat<(add_non_imm12 sh2add_op:$rs1, (XLenVT GPR:$rs2)),
           (TH_ADDSL GPR:$rs2, sh2add_op:$rs1, 2)>;
-def : Pat<(add sh3add_op:$rs1, non_imm12:$rs2),
+def : Pat<(add_non_imm12 sh3add_op:$rs1, (XLenVT GPR:$rs2)),
           (TH_ADDSL GPR:$rs2, sh3add_op:$rs1, 3)>;
 
 def : Pat<(add (mul_oneuse GPR:$rs1, (XLenVT 6)), GPR:$rs2),

llvm/lib/Target/RISCV/RISCVInstrInfoZb.td

@@ -230,16 +230,9 @@ def SimmShiftRightBy3XForm : SDNodeXForm<imm, [{
                                    N->getValueType(0));
 }]>;
 
-// Pattern to exclude simm12 immediates from matching.
-// Note: this will be removed once the GISel complex patterns for
-// SHXADD_UW is landed.
-def non_imm12 : PatLeaf<(XLenVT GPR:$a), [{
-  auto *C = dyn_cast<ConstantSDNode>(N);
-  return !C || !isInt<12>(C->getSExtValue());
-}]>;
-
+// Pattern to exclude simm12 immediates from matching, namely `non_imm12`.
 // GISel currently doesn't support PatFrag for leaf nodes, so `non_imm12`
-// cannot be directly supported in GISel. To reuse patterns between the two
+// cannot be implemented in that way. To reuse patterns between the two
 // ISels, we instead create PatFrag on operators that use `non_imm12`.
 class binop_with_non_imm12<SDPatternOperator binop>
   : PatFrag<(ops node:$x, node:$y), (binop node:$x, node:$y), [{
@@ -264,12 +257,11 @@ class binop_with_non_imm12<SDPatternOperator binop>
 def add_non_imm12       : binop_with_non_imm12<add>;
 def or_is_add_non_imm12 : binop_with_non_imm12<or_is_add>;
 
-def Shifted32OnesMask : PatLeaf<(imm), [{
-  uint64_t Imm = N->getZExtValue();
-  if (!isShiftedMask_64(Imm))
+def Shifted32OnesMask : IntImmLeaf<XLenVT, [{
+  if (!Imm.isShiftedMask())
     return false;
 
-  unsigned TrailingZeros = llvm::countr_zero(Imm);
+  unsigned TrailingZeros = Imm.countr_zero();
   return TrailingZeros > 0 && TrailingZeros < 32 &&
          Imm == UINT64_C(0xFFFFFFFF) << TrailingZeros;
 }], TrailingZeros>;
@@ -776,12 +768,11 @@ def : Pat<(i64 (add_non_imm12 (and (shl GPR:$rs1, (i64 3)), 0x7FFFFFFFF), (XLenV
           (SH3ADD_UW GPR:$rs1, GPR:$rs2)>;
 
 // More complex cases use a ComplexPattern.
-def : Pat<(i64 (add sh1add_uw_op:$rs1, non_imm12:$rs2)),
-          (SH1ADD_UW sh1add_uw_op:$rs1, GPR:$rs2)>;
-def : Pat<(i64 (add sh2add_uw_op:$rs1, non_imm12:$rs2)),
-          (SH2ADD_UW sh2add_uw_op:$rs1, GPR:$rs2)>;
-def : Pat<(i64 (add sh3add_uw_op:$rs1, non_imm12:$rs2)),
-          (SH3ADD_UW sh3add_uw_op:$rs1, GPR:$rs2)>;
+foreach i = {1,2,3} in {
+  defvar pat = !cast<ComplexPattern>("sh"#i#"add_uw_op");
+  def : Pat<(i64 (add_non_imm12 pat:$rs1, (XLenVT GPR:$rs2))),
+            (!cast<Instruction>("SH"#i#"ADD_UW") pat:$rs1, GPR:$rs2)>;
+}
 
 def : Pat<(i64 (add_non_imm12 (and GPR:$rs1, 0xFFFFFFFE), (XLenVT GPR:$rs2))),
           (SH1ADD (SRLIW GPR:$rs1, 1), GPR:$rs2)>;

llvm/test/CodeGen/RISCV/GlobalISel/instruction-select/zba-rv64.mir

@@ -150,3 +150,78 @@ body:             |
     %6:gprb(s64) = G_ADD %5, %1
     $x10 = COPY %6(s64)
 ...
+---
+name:            shXadd_uw_complex_shl_and
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10, $x11
+
+    ; CHECK-LABEL: name: shXadd_uw_complex_shl_and
+    ; CHECK: liveins: $x10, $x11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:gpr = COPY $x10
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:gpr = COPY $x11
+    ; CHECK-NEXT: [[SLLI:%[0-9]+]]:gpr = SLLI [[COPY]], 1
+    ; CHECK-NEXT: [[SH2ADD_UW:%[0-9]+]]:gpr = SH2ADD_UW [[SLLI]], [[COPY1]]
+    ; CHECK-NEXT: $x10 = COPY [[SH2ADD_UW]]
+    %0:gprb(s64) = COPY $x10
+    %1:gprb(s64) = COPY $x11
+
+    %2:gprb(s64) = G_CONSTANT i64 3
+    %3:gprb(s64) = G_SHL %0, %2
+    %4:gprb(s64) = G_CONSTANT i64 17179869183
+    %5:gprb(s64) = G_AND %3, %4
+
+    %6:gprb(s64) = G_ADD %5, %1
+    $x10 = COPY %6(s64)
+...
+---
+name:            slli_uw
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10
+
+    ; CHECK-LABEL: name: slli_uw
+    ; CHECK: liveins: $x10
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:gpr = COPY $x10
+    ; CHECK-NEXT: [[SLLI_UW:%[0-9]+]]:gpr = SLLI_UW [[COPY]], 7
+    ; CHECK-NEXT: $x10 = COPY [[SLLI_UW]]
+    %0:gprb(s64) = COPY $x10
+
+    %1:gprb(s64) = G_CONSTANT i64 4294967295
+    %2:gprb(s64) = G_AND %0, %1
+    %3:gprb(s64) = G_CONSTANT i64 7
+    %4:gprb(s64) = G_SHL %2, %3
+
+    $x10 = COPY %4(s64)
+...
+---
+name:            slli_uw_complex
+legalized:       true
+regBankSelected: true
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10
+
+    ; CHECK-LABEL: name: slli_uw_complex
+    ; CHECK: liveins: $x10
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:gpr = COPY $x10
+    ; CHECK-NEXT: [[SRLI:%[0-9]+]]:gpr = SRLI [[COPY]], 2
+    ; CHECK-NEXT: [[SLLI_UW:%[0-9]+]]:gpr = SLLI_UW [[SRLI]], 2
+    ; CHECK-NEXT: $x10 = COPY [[SLLI_UW]]
+    %0:gprb(s64) = COPY $x10
+
+    %1:gprb(s64) = G_CONSTANT i64 17179869180
+    %2:gprb(s64) = G_AND %0, %1
+
+    $x10 = COPY %2(s64)
+...