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[AMDGPU] Skip debug instructions when eliminating S_SET_GPR_IDX_ON/OFF #160715

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Merged
jayfoad merged 4 commits into from
Nov 4, 2025
Merged

[AMDGPU] Skip debug instructions when eliminating S_SET_GPR_IDX_ON/OFF #160715

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f8311a3
[AMDGPU] Skip debug instructions when eliminating S_SET_GPR_IDX_ON/OFF
jayfoad Sep 25, 2025
31e1d02
Skip all meta instructions
jayfoad Sep 25, 2025
574f561
Test KILL
jayfoad Sep 25, 2025
a9177fe
Test IMPLICIT_DEF. Revert special handling for meta instructions.
jayfoad Sep 26, 2025
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2 changes: 1 addition & 1 deletion llvm/lib/Target/AMDGPU/SIPreEmitPeephole.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -299,7 +299,7 @@ bool SIPreEmitPeephole::optimizeSetGPR(MachineInstr &First,
for (MachineBasicBlock::instr_iterator I = std::next(First.getIterator()),
E = MI.getIterator();
I != E; ++I) {
if (I->isBundle())
if (I->isBundle() || I->isMetaInstruction())
continue;
switch (I->getOpcode()) {
case AMDGPU::S_SET_GPR_IDX_MODE:
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20 changes: 20 additions & 0 deletions llvm/test/CodeGen/AMDGPU/set-gpr-idx-peephole.mir
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
# RUN: llc -mtriple=amdgcn -mcpu=gfx900 -run-pass si-pre-emit-peephole -verify-machineinstrs -o - %s | FileCheck -check-prefix=GCN %s -implicit-check-not=S_SET_GPR_IDX
# RUN: llc -mtriple=amdgcn -mcpu=gfx900 -run-pass si-pre-emit-peephole -verify-machineinstrs -o - %s -debugify-and-strip-all-safe | FileCheck -check-prefix=GCN %s -implicit-check-not=S_SET_GPR_IDX
# RUN: llc -mtriple=amdgcn -mcpu=gfx900 -passes si-pre-emit-peephole -o - %s | FileCheck -check-prefix=GCN %s -implicit-check-not=S_SET_GPR_IDX

---
Expand Down Expand Up @@ -40,6 +41,25 @@ body: |
S_SET_GPR_IDX_OFF implicit-def $mode, implicit $mode
...

---
name: kill_in_between
body: |
bb.0:
; GCN-LABEL: name: kill_in_between
; GCN: S_SET_GPR_IDX_ON $sgpr2, 1, implicit-def $m0, implicit-def $mode, implicit undef $m0, implicit $mode
; GCN-NEXT: $vgpr16 = V_MOV_B32_indirect_read undef $vgpr1, implicit $exec, implicit $m0, implicit $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5_vgpr6_vgpr7_vgpr8_vgpr9_vgpr10_vgpr11_vgpr12_vgpr13_vgpr14_vgpr15
; GCN-NEXT: KILL $sgpr0
; GCN-NEXT: $vgpr15 = V_MOV_B32_indirect_read undef $vgpr0, implicit $exec, implicit $m0, implicit killed $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5_vgpr6_vgpr7_vgpr8_vgpr9_vgpr10_vgpr11_vgpr12_vgpr13_vgpr14_vgpr15
; GCN-NEXT: S_SET_GPR_IDX_OFF implicit-def $mode, implicit $mode
S_SET_GPR_IDX_ON $sgpr2, 1, implicit-def $m0, implicit-def $mode, implicit undef $m0, implicit $mode
$vgpr16 = V_MOV_B32_indirect_read undef $vgpr1, implicit $exec, implicit $m0, implicit $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5_vgpr6_vgpr7_vgpr8_vgpr9_vgpr10_vgpr11_vgpr12_vgpr13_vgpr14_vgpr15
S_SET_GPR_IDX_OFF implicit-def $mode, implicit $mode
KILL $sgpr0
S_SET_GPR_IDX_ON killed $sgpr2, 1, implicit-def $m0, implicit-def $mode, implicit undef $m0, implicit $mode
$vgpr15 = V_MOV_B32_indirect_read undef $vgpr0, implicit $exec, implicit $m0, implicit killed $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5_vgpr6_vgpr7_vgpr8_vgpr9_vgpr10_vgpr11_vgpr12_vgpr13_vgpr14_vgpr15
S_SET_GPR_IDX_OFF implicit-def $mode, implicit $mode
...

---
name: valu_write_in_between
body: |
Expand Down