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[AMDGPU] si-peephole-sdwa: Remove dead code from createSDWAversion #141462

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Merged
merged 3 commits into from
May 26, 2025
Merged

[AMDGPU] si-peephole-sdwa: Remove dead code from createSDWAversion #141462

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[AMDGPU] si-peephole-sdwa: Remove dead code from createSDWAversion
frederik-h May 21, 2025
30f44dd
clang-format changes
frederik-h May 26, 2025
3d52eb3
trigger ci
frederik-h May 26, 2025
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57 changes: 7 additions & 50 deletions llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1273,65 +1273,22 @@ MachineInstr *SIPeepholeSDWA::createSDWAVersion(MachineInstr &MI) {
}
}

// Copy dst_sel if present, initialize otherwise if needed
if (AMDGPU::hasNamedOperand(SDWAOpcode, AMDGPU::OpName::dst_sel)) {
MachineOperand *DstSel = TII->getNamedOperand(MI, AMDGPU::OpName::dst_sel);
if (DstSel) {
SDWAInst.add(*DstSel);
} else {
SDWAInst.addImm(AMDGPU::SDWA::SdwaSel::DWORD);
}
}
// Initialize SDWA specific operands
if (AMDGPU::hasNamedOperand(SDWAOpcode, AMDGPU::OpName::dst_sel))
SDWAInst.addImm(AMDGPU::SDWA::SdwaSel::DWORD);

// Copy dst_unused if present, initialize otherwise if needed
if (AMDGPU::hasNamedOperand(SDWAOpcode, AMDGPU::OpName::dst_unused)) {
MachineOperand *DstUnused = TII->getNamedOperand(MI, AMDGPU::OpName::dst_unused);
if (DstUnused) {
SDWAInst.add(*DstUnused);
} else {
SDWAInst.addImm(AMDGPU::SDWA::DstUnused::UNUSED_PAD);
}
}
if (AMDGPU::hasNamedOperand(SDWAOpcode, AMDGPU::OpName::dst_unused))
SDWAInst.addImm(AMDGPU::SDWA::DstUnused::UNUSED_PAD);

// Copy src0_sel if present, initialize otherwise
assert(AMDGPU::hasNamedOperand(SDWAOpcode, AMDGPU::OpName::src0_sel));
MachineOperand *Src0Sel = TII->getNamedOperand(MI, AMDGPU::OpName::src0_sel);
if (Src0Sel) {
SDWAInst.add(*Src0Sel);
} else {
SDWAInst.addImm(AMDGPU::SDWA::SdwaSel::DWORD);
}
SDWAInst.addImm(AMDGPU::SDWA::SdwaSel::DWORD);

// Copy src1_sel if present, initialize otherwise if needed
if (Src1) {
assert(AMDGPU::hasNamedOperand(SDWAOpcode, AMDGPU::OpName::src1_sel));
MachineOperand *Src1Sel = TII->getNamedOperand(MI, AMDGPU::OpName::src1_sel);
if (Src1Sel) {
SDWAInst.add(*Src1Sel);
} else {
SDWAInst.addImm(AMDGPU::SDWA::SdwaSel::DWORD);
}
SDWAInst.addImm(AMDGPU::SDWA::SdwaSel::DWORD);
}

// Check for a preserved register that needs to be copied.
auto *DstUnused = TII->getNamedOperand(MI, AMDGPU::OpName::dst_unused);
if (DstUnused &&
DstUnused->getImm() == AMDGPU::SDWA::DstUnused::UNUSED_PRESERVE) {
// We expect, if we are here, that the instruction was already in it's SDWA form,
// with a tied operand.
assert(Dst && Dst->isTied());
assert(Opcode == static_cast<unsigned int>(SDWAOpcode));
// We also expect a vdst, since sdst can't preserve.
auto PreserveDstIdx = AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::vdst);
assert(PreserveDstIdx != -1);

auto TiedIdx = MI.findTiedOperandIdx(PreserveDstIdx);
auto Tied = MI.getOperand(TiedIdx);

SDWAInst.add(Tied);
SDWAInst->tieOperands(PreserveDstIdx, SDWAInst->getNumOperands() - 1);
}

MachineInstr *Ret = SDWAInst.getInstr();
TII->fixImplicitOperands(*Ret);
return Ret;
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