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[SPIR-V] fix return type for OpAtomicCompareExchange #154297

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Merged
Naghasan merged 4 commits into from
Aug 20, 2025
Merged

[SPIR-V] fix return type for OpAtomicCompareExchange #154297

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91dec04
[SPIR-V] fix return type for OpAtomicCompareExchange
simeonschaub Aug 19, 2025
c6eb12e
relax test
simeonschaub Aug 19, 2025
801089b
don't assume spirv-val is available
simeonschaub Aug 19, 2025
82f602b
simplify test
simeonschaub Aug 20, 2025
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3 changes: 1 addition & 2 deletions llvm/lib/Target/SPIRV/SPIRVBuiltins.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -802,10 +802,9 @@ static bool buildAtomicCompareExchangeInst(
MRI->setRegClass(Tmp, GR->getRegClass(SpvDesiredTy));
GR->assignSPIRVTypeToVReg(SpvDesiredTy, Tmp, MIRBuilder.getMF());

SPIRVType *IntTy = GR->getOrCreateSPIRVIntegerType(32, MIRBuilder);
MIRBuilder.buildInstr(Opcode)
.addDef(Tmp)
.addUse(GR->getSPIRVTypeID(IntTy))
.addUse(GR->getSPIRVTypeID(SpvDesiredTy))
.addUse(ObjectPtr)
.addUse(ScopeReg)
.addUse(MemSemEqualReg)
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30 changes: 30 additions & 0 deletions llvm/test/CodeGen/SPIRV/AtomicCompareExchange64BitPhiNode.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,30 @@
; RUN: llc -O0 -mtriple=spirv64-unknown-unknown %s -o - | FileCheck %s --check-prefix=CHECK-SPIRV
; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv64-unknown-unknown %s -o - -filetype=obj | spirv-val %}

; Regression test for issue https://github.com/llvm/llvm-project/issues/152863
; Ensure OpAtomicCompareExchange returns the correct i64 type when used in phi nodes.
; Previously, this would generate invalid SPIR-V where the atomic operation returned
; uint (32-bit) but the phi node expected ulong (64-bit), causing validation errors.

; CHECK-SPIRV-DAG: %[[#Long:]] = OpTypeInt 64 0
; CHECK-SPIRV-DAG: %[[#Ptr:]] = OpTypePointer CrossWorkgroup %[[#Long]]
; CHECK-SPIRV-DAG: %[[#Zero64:]] = OpConstantNull %[[#Long]]

; Verify that both the phi node and atomic operation use the same i64 type
; CHECK-SPIRV: %[[#ValuePhi:]] = OpPhi %[[#Long]] %[[#Zero64]] %[[#]] %[[#AtomicResult:]] %[[#]]
; CHECK-SPIRV: %[[#AtomicResult]] = OpAtomicCompareExchange %[[#Long]] %[[#]] %[[#]] %[[#]] %[[#]] %[[#Zero64]] %[[#ValuePhi]]

target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-G1"
target triple = "spirv64-unknown-unknown"

declare i64 @_Z14atomic_cmpxchgPU8CLglobalVlll(ptr addrspace(1), i64, i64)

define spir_kernel void @test_atomic_cmpxchg_phi(ptr addrspace(1) %ptr) {
conversion:
br label %L6

L6: ; preds = %L6, %conversion
%value_phi = phi i64 [ 0, %conversion ], [ %1, %L6 ]
%1 = call i64 @_Z14atomic_cmpxchgPU8CLglobalVlll(ptr addrspace(1) %ptr, i64 %value_phi, i64 0)
br label %L6
}