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release/21.x: [RISCV] Correct the CFA offsets for stack probing. (#166616) #166783

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Merged
merged 1 commit into from
Nov 12, 2025
Merged

release/21.x: [RISCV] Correct the CFA offsets for stack probing. (#166616) #166783

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6 changes: 4 additions & 2 deletions llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -768,6 +768,8 @@ void RISCVFrameLowering::allocateStack(MachineBasicBlock &MBB,

// Unroll the probe loop depending on the number of iterations.
if (Offset < ProbeSize * 5) {
uint64_t CFAAdjust = RealStackSize - Offset;

uint64_t CurrentOffset = 0;
while (CurrentOffset + ProbeSize <= Offset) {
RI->adjustReg(MBB, MBBI, DL, SPReg, SPReg,
Expand All @@ -781,15 +783,15 @@ void RISCVFrameLowering::allocateStack(MachineBasicBlock &MBB,

CurrentOffset += ProbeSize;
if (EmitCFI)
CFIBuilder.buildDefCFAOffset(CurrentOffset);
CFIBuilder.buildDefCFAOffset(CurrentOffset + CFAAdjust);
}

uint64_t Residual = Offset - CurrentOffset;
if (Residual) {
RI->adjustReg(MBB, MBBI, DL, SPReg, SPReg,
StackOffset::getFixed(-Residual), Flag, getStackAlign());
if (EmitCFI)
CFIBuilder.buildDefCFAOffset(Offset);
CFIBuilder.buildDefCFAOffset(RealStackSize);

if (DynAllocation) {
// s[d|w] zero, 0(sp)
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8 changes: 4 additions & 4 deletions llvm/test/CodeGen/RISCV/rvv/stack-probing-dynamic.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -460,9 +460,9 @@ define void @reserved_call_frame(i64 %n) #0 {
; RV64I-NEXT: lui a0, 1
; RV64I-NEXT: sub sp, sp, a0
; RV64I-NEXT: sd zero, 0(sp)
; RV64I-NEXT: .cfi_def_cfa_offset 4096
; RV64I-NEXT: .cfi_def_cfa_offset 6128
; RV64I-NEXT: addi sp, sp, -48
; RV64I-NEXT: .cfi_def_cfa_offset 4144
; RV64I-NEXT: .cfi_def_cfa_offset 6176
; RV64I-NEXT: lui a0, 1
; RV64I-NEXT: add a0, sp, a0
; RV64I-NEXT: call callee_stack_args
Expand All @@ -485,9 +485,9 @@ define void @reserved_call_frame(i64 %n) #0 {
; RV32I-NEXT: lui a0, 1
; RV32I-NEXT: sub sp, sp, a0
; RV32I-NEXT: sw zero, 0(sp)
; RV32I-NEXT: .cfi_def_cfa_offset 4096
; RV32I-NEXT: .cfi_def_cfa_offset 6128
; RV32I-NEXT: addi sp, sp, -80
; RV32I-NEXT: .cfi_def_cfa_offset 4176
; RV32I-NEXT: .cfi_def_cfa_offset 6208
; RV32I-NEXT: lui a0, 1
; RV32I-NEXT: addi a0, a0, 36
; RV32I-NEXT: add a0, sp, a0
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