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[AMDGPU] Use implicit operand to preserve liveness of COPY #164911

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Merged
merged 1 commit into from
Oct 27, 2025
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Merged

[AMDGPU] Use implicit operand to preserve liveness of COPY #164911

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6 changes: 5 additions & 1 deletion llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1874,9 +1874,13 @@ void SIRegisterInfo::buildSpillLoadStore(
}

bool IsSrcDstDef = SrcDstRegState & RegState::Define;
bool PartialReloadCopy = (RemEltSize != EltSize) && !IsStore;
if (NeedSuperRegImpOperand &&
(IsFirstSubReg || (IsLastSubReg && !IsSrcDstDef)))
(IsFirstSubReg || (IsLastSubReg && !IsSrcDstDef))) {
MIB.addReg(ValueReg, RegState::Implicit | SrcDstRegState);
if (PartialReloadCopy)
MIB.addReg(ValueReg, RegState::Implicit);
}

// The epilog restore of a wwm-scratch register can cause undesired
// optimization during machine-cp post PrologEpilogInserter if the same
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10 changes: 5 additions & 5 deletions llvm/test/CodeGen/AMDGPU/pei-build-spill-partial-agpr.mir
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Original file line number Diff line number Diff line change
Expand Up @@ -73,7 +73,7 @@ body: |
; FLATSCR-V2A-NEXT: $agpr0 = V_ACCVGPR_WRITE_B32_e64 killed $vgpr1, implicit $exec, implicit-def $vgpr0_vgpr1, implicit $vgpr0_vgpr1
; FLATSCR-V2A-NEXT: SCRATCH_STORE_DWORD_SADDR killed $vgpr0, $sgpr32, 0, 0, implicit $exec, implicit $flat_scr, implicit killed $vgpr0_vgpr1 :: (store (s32) into %stack.0, addrspace 5)
; FLATSCR-V2A-NEXT: $vgpr1 = V_ACCVGPR_READ_B32_e64 $agpr0, implicit $exec, implicit-def $vgpr0_vgpr1
; FLATSCR-V2A-NEXT: $vgpr0 = SCRATCH_LOAD_DWORD_SADDR $sgpr32, 0, 0, implicit $exec, implicit $flat_scr, implicit-def $vgpr0_vgpr1 :: (load (s32) from %stack.0, addrspace 5)
; FLATSCR-V2A-NEXT: $vgpr0 = SCRATCH_LOAD_DWORD_SADDR $sgpr32, 0, 0, implicit $exec, implicit $flat_scr, implicit-def $vgpr0_vgpr1, implicit $vgpr0_vgpr1 :: (load (s32) from %stack.0, addrspace 5)
; FLATSCR-V2A-NEXT: S_ENDPGM 0
$vgpr0_vgpr1 = IMPLICIT_DEF
SI_SPILL_V64_SAVE killed $vgpr0_vgpr1, %stack.0, $sgpr32, 0, implicit $exec :: (store (s64) into %stack.0, align 4, addrspace 5)
Expand Down Expand Up @@ -112,7 +112,7 @@ body: |
; FLATSCR-V2A-NEXT: $agpr0 = V_ACCVGPR_WRITE_B32_e64 killed $vgpr2, implicit $exec, implicit-def $vgpr0_vgpr1_vgpr2, implicit $vgpr0_vgpr1_vgpr2
; FLATSCR-V2A-NEXT: SCRATCH_STORE_DWORDX2_SADDR killed $vgpr0_vgpr1, $sgpr32, 0, 0, implicit $exec, implicit $flat_scr, implicit killed $vgpr0_vgpr1_vgpr2 :: (store (s64) into %stack.0, align 4, addrspace 5)
; FLATSCR-V2A-NEXT: $vgpr2 = V_ACCVGPR_READ_B32_e64 $agpr0, implicit $exec, implicit-def $vgpr0_vgpr1_vgpr2
; FLATSCR-V2A-NEXT: $vgpr0_vgpr1 = SCRATCH_LOAD_DWORDX2_SADDR $sgpr32, 0, 0, implicit $exec, implicit $flat_scr, implicit-def $vgpr0_vgpr1_vgpr2 :: (load (s64) from %stack.0, align 4, addrspace 5)
; FLATSCR-V2A-NEXT: $vgpr0_vgpr1 = SCRATCH_LOAD_DWORDX2_SADDR $sgpr32, 0, 0, implicit $exec, implicit $flat_scr, implicit-def $vgpr0_vgpr1_vgpr2, implicit $vgpr0_vgpr1_vgpr2 :: (load (s64) from %stack.0, align 4, addrspace 5)
; FLATSCR-V2A-NEXT: S_ENDPGM 0
$vgpr0_vgpr1_vgpr2 = IMPLICIT_DEF
SI_SPILL_V96_SAVE killed $vgpr0_vgpr1_vgpr2, %stack.0, $sgpr32, 0, implicit $exec :: (store (s96) into %stack.0, align 4, addrspace 5)
Expand Down Expand Up @@ -157,7 +157,7 @@ body: |
; FLATSCR-V2A-NEXT: $vgpr3 = V_ACCVGPR_READ_B32_e64 $agpr0, implicit $exec, implicit-def $vgpr0_vgpr1_vgpr2_vgpr3
; FLATSCR-V2A-NEXT: $vgpr2 = V_ACCVGPR_READ_B32_e64 $agpr1, implicit $exec, implicit $vgpr0_vgpr1_vgpr2_vgpr3
; FLATSCR-V2A-NEXT: $vgpr1 = V_ACCVGPR_READ_B32_e64 $agpr2, implicit $exec, implicit $vgpr0_vgpr1_vgpr2_vgpr3
; FLATSCR-V2A-NEXT: $vgpr0 = SCRATCH_LOAD_DWORD_SADDR $sgpr32, 0, 0, implicit $exec, implicit $flat_scr, implicit-def $vgpr0_vgpr1_vgpr2_vgpr3 :: (load (s32) from %stack.0, addrspace 5)
; FLATSCR-V2A-NEXT: $vgpr0 = SCRATCH_LOAD_DWORD_SADDR $sgpr32, 0, 0, implicit $exec, implicit $flat_scr, implicit-def $vgpr0_vgpr1_vgpr2_vgpr3, implicit $vgpr0_vgpr1_vgpr2_vgpr3 :: (load (s32) from %stack.0, addrspace 5)
; FLATSCR-V2A-NEXT: S_ENDPGM 0
$vgpr0_vgpr1_vgpr2_vgpr3 = IMPLICIT_DEF
SI_SPILL_V128_SAVE killed $vgpr0_vgpr1_vgpr2_vgpr3, %stack.0, $sgpr32, 0, implicit $exec :: (store (s128) into %stack.0, align 4, addrspace 5)
Expand Down Expand Up @@ -203,7 +203,7 @@ body: |
; FLATSCR-V2A-NEXT: $agpr0 = V_ACCVGPR_WRITE_B32_e64 killed $vgpr4, implicit $exec, implicit killed $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4
; FLATSCR-V2A-NEXT: $vgpr3 = V_ACCVGPR_READ_B32_e64 $agpr1, implicit $exec, implicit-def $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4
; FLATSCR-V2A-NEXT: $vgpr2 = V_ACCVGPR_READ_B32_e64 $agpr2, implicit $exec, implicit $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4
; FLATSCR-V2A-NEXT: $vgpr0_vgpr1 = SCRATCH_LOAD_DWORDX2_SADDR $sgpr32, 0, 0, implicit $exec, implicit $flat_scr, implicit-def $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4 :: (load (s64) from %stack.0, align 4, addrspace 5)
; FLATSCR-V2A-NEXT: $vgpr0_vgpr1 = SCRATCH_LOAD_DWORDX2_SADDR $sgpr32, 0, 0, implicit $exec, implicit $flat_scr, implicit-def $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4, implicit $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4 :: (load (s64) from %stack.0, align 4, addrspace 5)
; FLATSCR-V2A-NEXT: $vgpr4 = V_ACCVGPR_READ_B32_e64 $agpr0, implicit $exec, implicit $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4
; FLATSCR-V2A-NEXT: S_ENDPGM 0
$vgpr0_vgpr1_vgpr2_vgpr3_vgpr4 = IMPLICIT_DEF
Expand Down Expand Up @@ -255,7 +255,7 @@ body: |
; FLATSCR-V2A-NEXT: $vgpr3 = V_ACCVGPR_READ_B32_e64 $agpr2, implicit $exec, implicit-def $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5
; FLATSCR-V2A-NEXT: $vgpr2 = V_ACCVGPR_READ_B32_e64 $agpr3, implicit $exec, implicit $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5
; FLATSCR-V2A-NEXT: $vgpr1 = V_ACCVGPR_READ_B32_e64 $agpr4, implicit $exec, implicit $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5
; FLATSCR-V2A-NEXT: $vgpr0 = SCRATCH_LOAD_DWORD_SADDR $sgpr32, 0, 0, implicit $exec, implicit $flat_scr, implicit-def $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5 :: (load (s32) from %stack.0, addrspace 5)
; FLATSCR-V2A-NEXT: $vgpr0 = SCRATCH_LOAD_DWORD_SADDR $sgpr32, 0, 0, implicit $exec, implicit $flat_scr, implicit-def $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5, implicit $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5 :: (load (s32) from %stack.0, addrspace 5)
; FLATSCR-V2A-NEXT: $vgpr5 = V_ACCVGPR_READ_B32_e64 $agpr0, implicit $exec, implicit $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5
; FLATSCR-V2A-NEXT: $vgpr4 = V_ACCVGPR_READ_B32_e64 $agpr1, implicit $exec, implicit $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5
; FLATSCR-V2A-NEXT: S_ENDPGM 0
Expand Down
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