[llvm] dd315a5 - [AMDGPU] Set success flag for weak cmpxchg in LowerBufferFatPointers (#203033)

[via llvm-commits]

Author: Arseniy Obolenskiy
Date: 2026-06-11T04:55:09+02:00
New Revision: dd315a54d0e95a98948fb6b57d27f0cce4418198

URL: https://github.com/llvm/llvm-project/commit/dd315a54d0e95a98948fb6b57d27f0cce4418198
DIFF: https://github.com/llvm/llvm-project/commit/dd315a54d0e95a98948fb6b57d27f0cce4418198.diff

LOG: [AMDGPU] Set success flag for weak cmpxchg in LowerBufferFatPointers (#203033)

Added: 
    

Modified: 
    llvm/lib/Target/AMDGPU/AMDGPULowerBufferFatPointers.cpp
    llvm/test/CodeGen/AMDGPU/lower-buffer-fat-pointers-memops.ll

Removed: 
    


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diff  --git a/llvm/lib/Target/AMDGPU/AMDGPULowerBufferFatPointers.cpp b/llvm/lib/Target/AMDGPU/AMDGPULowerBufferFatPointers.cpp
index 679f7d5d8329f..300c2f8782ae1 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPULowerBufferFatPointers.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPULowerBufferFatPointers.cpp
@@ -1880,10 +1880,8 @@ PtrParts SplitPtrStructs::visitAtomicCmpXchgInst(AtomicCmpXchgInst &AI) {
 
   Value *Res = PoisonValue::get(AI.getType());
   Res = IRB.CreateInsertValue(Res, Call, 0);
-  if (!AI.isWeak()) {
-    Value *Succeeded = IRB.CreateICmpEQ(Call, AI.getCompareOperand());
-    Res = IRB.CreateInsertValue(Res, Succeeded, 1);
-  }
+  Value *Succeeded = IRB.CreateICmpEQ(Call, AI.getCompareOperand());
+  Res = IRB.CreateInsertValue(Res, Succeeded, 1);
   SplitUsers.insert(&AI);
   AI.replaceAllUsesWith(Res);
   return {nullptr, nullptr};

diff  --git a/llvm/test/CodeGen/AMDGPU/lower-buffer-fat-pointers-memops.ll b/llvm/test/CodeGen/AMDGPU/lower-buffer-fat-pointers-memops.ll
index ca51a08920aba..756a6af4ccbcd 100644
--- a/llvm/test/CodeGen/AMDGPU/lower-buffer-fat-pointers-memops.ll
+++ b/llvm/test/CodeGen/AMDGPU/lower-buffer-fat-pointers-memops.ll
@@ -175,7 +175,9 @@ define {i32, i1} @cmpxchg_weak(ptr addrspace(8) %buf, i32 %wanted, i32 %new) {
 ; CHECK-NEXT:    [[RET:%.*]] = call i32 @llvm.amdgcn.raw.ptr.buffer.atomic.cmpswap.i32(i32 [[NEW]], i32 [[WANTED]], ptr addrspace(8) align 4 [[BUF]], i32 16, i32 0, i32 0)
 ; CHECK-NEXT:    fence syncscope("wavefront") acquire
 ; CHECK-NEXT:    [[TMP1:%.*]] = insertvalue { i32, i1 } poison, i32 [[RET]], 0
-; CHECK-NEXT:    ret { i32, i1 } [[TMP1]]
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp eq i32 [[RET]], [[WANTED]]
+; CHECK-NEXT:    [[TMP3:%.*]] = insertvalue { i32, i1 } [[TMP1]], i1 [[TMP2]], 1
+; CHECK-NEXT:    ret { i32, i1 } [[TMP3]]
 ;
   %base = addrspacecast ptr addrspace(8) %buf to ptr addrspace(7)
   %p = getelementptr i32, ptr addrspace(7) %base, i32 4