https://github.com/arsenm created
https://github.com/llvm/llvm-project/pull/149291
When searching for an existing VGPR source for an AGPR to AGPR
copy on gfx908, this wasn't verifying the vgpr wasn't killed by
other prior uses.
>From 70034b791643f35f8a8e69d0e161d10c9c8eeb60 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <matthew.arsena...@amd.com>
Date: Thu, 17 Jul 2025 20:26:08 +0900
Subject: [PATCH] AMDGPU: Fix introducing use of killed vgpr in gfx908 agpr
copy
When searching for an existing VGPR source for an AGPR to AGPR
copy on gfx908, this wasn't verifying the vgpr wasn't killed by
other prior uses.
---
llvm/lib/Target/AMDGPU/SIInstrInfo.cpp | 3 +-
llvm/test/CodeGen/AMDGPU/accvgpr-copy.mir | 83 +++++++++++++++++++++++
2 files changed, 85 insertions(+), 1 deletion(-)
diff --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
index b1116974642c9..c8935f0cb6034 100644
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -687,7 +687,8 @@ static void indirectCopyToAGPR(const SIInstrInfo &TII,
if (!SafeToPropagate)
break;
- DefOp.setIsKill(false);
+ for (auto I = Def; I != MI; ++I)
+ I->clearRegisterKills(DefOp.getReg(), &RI);
}
MachineInstrBuilder Builder =
diff --git a/llvm/test/CodeGen/AMDGPU/accvgpr-copy.mir
b/llvm/test/CodeGen/AMDGPU/accvgpr-copy.mir
index 2bd1b8bf3f3f6..d22a4b978980f 100644
--- a/llvm/test/CodeGen/AMDGPU/accvgpr-copy.mir
+++ b/llvm/test/CodeGen/AMDGPU/accvgpr-copy.mir
@@ -45,6 +45,9 @@
define amdgpu_kernel void @copy_agpr_to_agpr_tuple() #0 { ret void }
define amdgpu_kernel void @copy_agpr_to_agpr_tuple_kill() #0 { ret void }
+ define amdgpu_kernel void @look_for_vgpr_killed() #0 { ret void }
+ define amdgpu_kernel void @look_for_vgpr_killed_tuple() #0 { ret void }
+
attributes #0 = { "amdgpu-flat-work-group-size"="1,256" }
...
@@ -1517,3 +1520,83 @@ body: |
renamable $agpr4_agpr5_agpr6_agpr7 = COPY renamable killed
$agpr0_agpr1_agpr2_agpr3, implicit $exec
S_ENDPGM 0, implicit $agpr4_agpr5_agpr6_agpr7
...
+
+# Make sure the expansion of the a-to-a copy doesn't introduce a use
+# after kill of the source vgpr
+---
+name: look_for_vgpr_killed
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: $agpr0
+
+ ; GFX908-LABEL: name: look_for_vgpr_killed
+ ; GFX908: liveins: $agpr0
+ ; GFX908-NEXT: {{ $}}
+ ; GFX908-NEXT: $vgpr0 = V_MOV_B32_e32 0, implicit $exec
+ ; GFX908-NEXT: $agpr0 = V_ACCVGPR_WRITE_B32_e64 $vgpr0, implicit $exec
+ ; GFX908-NEXT: S_NOP 0, implicit $vgpr0
+ ; GFX908-NEXT: $agpr1 = V_ACCVGPR_WRITE_B32_e64 $vgpr0, implicit $exec
+ ;
+ ; GFX90A-LABEL: name: look_for_vgpr_killed
+ ; GFX90A: liveins: $agpr0
+ ; GFX90A-NEXT: {{ $}}
+ ; GFX90A-NEXT: $vgpr0 = V_MOV_B32_e32 0, implicit $exec
+ ; GFX90A-NEXT: $agpr0 = V_ACCVGPR_WRITE_B32_e64 $vgpr0, implicit $exec
+ ; GFX90A-NEXT: S_NOP 0, implicit killed $vgpr0
+ ; GFX90A-NEXT: $agpr1 = V_ACCVGPR_MOV_B32 $agpr0, implicit $exec
+ ;
+ ; GFX942-LABEL: name: look_for_vgpr_killed
+ ; GFX942: liveins: $agpr0
+ ; GFX942-NEXT: {{ $}}
+ ; GFX942-NEXT: $vgpr0 = V_MOV_B32_e32 0, implicit $exec
+ ; GFX942-NEXT: $agpr0 = V_ACCVGPR_WRITE_B32_e64 $vgpr0, implicit $exec
+ ; GFX942-NEXT: S_NOP 0, implicit killed $vgpr0
+ ; GFX942-NEXT: $agpr1 = V_ACCVGPR_MOV_B32 $agpr0, implicit $exec
+ $vgpr0 = V_MOV_B32_e32 0, implicit $exec
+ $agpr0 = COPY $vgpr0
+ S_NOP 0, implicit killed $vgpr0
+ $agpr1 = COPY $agpr0
+
+...
+
+---
+name: look_for_vgpr_killed_tuple
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: $agpr0
+
+ ; GFX908-LABEL: name: look_for_vgpr_killed_tuple
+ ; GFX908: liveins: $agpr0
+ ; GFX908-NEXT: {{ $}}
+ ; GFX908-NEXT: $vgpr0 = V_MOV_B32_e32 0, implicit $exec, implicit-def
$vgpr0_vgpr1
+ ; GFX908-NEXT: $vgpr1 = V_MOV_B32_e32 1, implicit $exec
+ ; GFX908-NEXT: $agpr0 = V_ACCVGPR_WRITE_B32_e64 $vgpr0, implicit $exec
+ ; GFX908-NEXT: S_NOP 0, implicit $vgpr0_vgpr1
+ ; GFX908-NEXT: $agpr1 = V_ACCVGPR_WRITE_B32_e64 $vgpr0, implicit $exec
+ ;
+ ; GFX90A-LABEL: name: look_for_vgpr_killed_tuple
+ ; GFX90A: liveins: $agpr0
+ ; GFX90A-NEXT: {{ $}}
+ ; GFX90A-NEXT: $vgpr0 = V_MOV_B32_e32 0, implicit $exec, implicit-def
$vgpr0_vgpr1
+ ; GFX90A-NEXT: $vgpr1 = V_MOV_B32_e32 1, implicit $exec
+ ; GFX90A-NEXT: $agpr0 = V_ACCVGPR_WRITE_B32_e64 $vgpr0, implicit $exec
+ ; GFX90A-NEXT: S_NOP 0, implicit killed $vgpr0_vgpr1
+ ; GFX90A-NEXT: $agpr1 = V_ACCVGPR_MOV_B32 $agpr0, implicit $exec
+ ;
+ ; GFX942-LABEL: name: look_for_vgpr_killed_tuple
+ ; GFX942: liveins: $agpr0
+ ; GFX942-NEXT: {{ $}}
+ ; GFX942-NEXT: $vgpr0 = V_MOV_B32_e32 0, implicit $exec, implicit-def
$vgpr0_vgpr1
+ ; GFX942-NEXT: $vgpr1 = V_MOV_B32_e32 1, implicit $exec
+ ; GFX942-NEXT: $agpr0 = V_ACCVGPR_WRITE_B32_e64 $vgpr0, implicit $exec
+ ; GFX942-NEXT: S_NOP 0, implicit killed $vgpr0_vgpr1
+ ; GFX942-NEXT: $agpr1 = V_ACCVGPR_MOV_B32 $agpr0, implicit $exec
+ $vgpr0 = V_MOV_B32_e32 0, implicit $exec, implicit-def $vgpr0_vgpr1
+ $vgpr1 = V_MOV_B32_e32 1, implicit $exec
+ $agpr0 = COPY $vgpr0
+ S_NOP 0, implicit killed $vgpr0_vgpr1
+ $agpr1 = COPY $agpr0
+
+...
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