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[SPIRV][HLSL] Fix assert with cbuffers through constexpr #164555

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Merged
merged 1 commit into from
Oct 22, 2025
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[SPIRV][HLSL] Fix assert with cbuffers through constexpr #164555

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14 changes: 8 additions & 6 deletions llvm/lib/Target/SPIRV/SPIRVCBufferAccess.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/IntrinsicsSPIRV.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/ReplaceConstant.h"

#define DEBUG_TYPE "spirv-cbuffer-access"
using namespace llvm;
Expand All @@ -57,6 +58,12 @@ static bool replaceCBufferAccesses(Module &M) {
if (!CBufMD)
return false;

SmallVector<Constant *> CBufferGlobals;
for (const hlsl::CBufferMapping &Mapping : *CBufMD)
for (const hlsl::CBufferMember &Member : Mapping.Members)
CBufferGlobals.push_back(Member.GV);
convertUsersOfConstantsToInstructions(CBufferGlobals);

for (const hlsl::CBufferMapping &Mapping : *CBufMD) {
Instruction *HandleDef = findHandleDef(Mapping.Handle);
if (!HandleDef) {
Expand All @@ -80,12 +87,7 @@ static bool replaceCBufferAccesses(Module &M) {
Value *GetPointerCall = Builder.CreateIntrinsic(
PtrType, Intrinsic::spv_resource_getpointer, {HandleDef, IndexVal});

// We cannot use replaceAllUsesWith here because some uses may be
// ConstantExprs, which cannot be replaced with non-constants.
SmallVector<User *, 4> Users(MemberGV->users());
for (User *U : Users) {
U->replaceUsesOfWith(MemberGV, GetPointerCall);
}
MemberGV->replaceAllUsesWith(GetPointerCall);
}
}

Expand Down
6 changes: 2 additions & 4 deletions llvm/test/CodeGen/SPIRV/hlsl-resources/cbuffer.ll
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
; RUN: llc -O0 -verify-machineinstrs -mtriple=spirv1.6-vulkan1.3-library %s -o - | FileCheck %s
; Test that uses of cbuffer members inside ConstantExprs are handled correctly.
; Test that uses of cbuffer members are handled correctly.

; CHECK-DAG: OpDecorate %[[MyCBuffer:[0-9]+]] DescriptorSet 0
; CHECK-DAG: OpDecorate %[[MyCBuffer]] Binding 0
Expand Down Expand Up @@ -37,10 +37,8 @@ entry:
; CHECK: %[[tmp_ptr:[0-9]+]] = OpAccessChain {{%[0-9]+}} %[[tmp]] %[[uint_0]] %[[uint_0]]
; CHECK: %[[v_ptr:.+]] = OpAccessChain %[[_ptr_Uniform_v4float]] %[[tmp]] %[[uint_0]] %[[uint_1]]
; CHECK: %[[s_ptr_gep:[0-9]+]] = OpInBoundsAccessChain %[[_ptr_Uniform_float]] %[[tmp_ptr]] %[[uint_0]] %[[uint_1]]
%gep = getelementptr inbounds %MyStruct, ptr addrspace(12) @s, i32 0, i32 0, i32 1

; CHECK: %[[s_val:.+]] = OpLoad %[[float]] %[[s_ptr_gep]]
%load_from_gep = load float, ptr addrspace(12) %gep, align 4
%load_from_gep = load float, ptr addrspace(12) getelementptr inbounds (%MyStruct, ptr addrspace(12) @s, i32 0, i32 0, i32 1), align 4

; CHECK: %[[v_val:.+]] = OpLoad %[[v4float]] %[[v_ptr]]
%load_v = load <4 x float>, ptr addrspace(12) @v, align 16
Expand Down