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[AMDGPU] Consider FLAT instructions for VMEM hazard detection #137170

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[AMDGPU] Consider FLAT instructions for VMEM hazard detection #137170

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c178e63
[AMDGPU] Consider FLAT instructions for VMEM hazard detection
ro-i Apr 24, 2025
02e4833
remove ISA quote in test
ro-i May 28, 2025
a550fa4
fix bug
ro-i May 28, 2025
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10 changes: 4 additions & 6 deletions llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1417,9 +1417,8 @@ static bool shouldRunLdsBranchVmemWARHazardFixup(const MachineFunction &MF,
bool HasVmem = false;
for (auto &MBB : MF) {
for (auto &MI : MBB) {
HasLds |= SIInstrInfo::isDS(MI);
HasVmem |= (SIInstrInfo::isVMEM(MI) && !SIInstrInfo::isFLAT(MI)) ||
SIInstrInfo::isSegmentSpecificFLAT(MI);
HasLds |= SIInstrInfo::isDS(MI) || SIInstrInfo::isLDSDMA(MI);
HasVmem |= SIInstrInfo::isVMEM(MI);
if (HasLds && HasVmem)
return true;
}
Expand All @@ -1441,10 +1440,9 @@ bool GCNHazardRecognizer::fixLdsBranchVmemWARHazard(MachineInstr *MI) {
assert(!ST.hasExtendedWaitCounts());

auto IsHazardInst = [](const MachineInstr &MI) {
if (SIInstrInfo::isDS(MI))
if (SIInstrInfo::isDS(MI) || SIInstrInfo::isLDSDMA(MI))
return 1;
if ((SIInstrInfo::isVMEM(MI) && !SIInstrInfo::isFLAT(MI)) ||
SIInstrInfo::isSegmentSpecificFLAT(MI))
if (SIInstrInfo::isVMEM(MI))
return 2;
return 0;
};
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5 changes: 3 additions & 2 deletions llvm/test/CodeGen/AMDGPU/lds-branch-vmem-hazard.mir
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Expand Up @@ -269,11 +269,12 @@ body: |
S_ENDPGM 0
...

# GCN-LABEL: name: no_hazard_lds_branch_flat
# GCN-LABEL: name: hazard_lds_branch_flat
# GCN: bb.1:
# GFX10-NEXT: S_WAITCNT_VSCNT undef $sgpr_null, 0
# GCN-NEXT: FLAT_LOAD_DWORD
---
name: no_hazard_lds_branch_flat
name: hazard_lds_branch_flat
body: |
bb.0:
successors: %bb.1
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