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InstCombine: Check GEP operand is available #160438

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Merged
merged 1 commit into from
Sep 25, 2025
+31 −2
Merged

InstCombine: Check GEP operand is available #160438

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14 changes: 12 additions & 2 deletions llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -338,8 +338,18 @@ bool PointerReplacer::collectUsers() {
if (!TryPushInstOperand(TrueInst) || !TryPushInstOperand(FalseInst))
return false;
} else if (auto *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
UsersToReplace.insert(GEP);
PushUsersToWorklist(GEP);
auto *PtrOp = dyn_cast<Instruction>(GEP->getPointerOperand());
if (!PtrOp)
return false;
if (isAvailable(PtrOp)) {
UsersToReplace.insert(GEP);
PushUsersToWorklist(GEP);
continue;
}

Worklist.emplace_back(GEP);
if (!TryPushInstOperand(PtrOp))
return false;
} else if (auto *MI = dyn_cast<MemTransferInst>(Inst)) {
if (MI->isVolatile())
return false;
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19 changes: 19 additions & 0 deletions llvm/test/Transforms/InstCombine/AMDGPU/ptr-replace-alloca.ll
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Expand Up @@ -109,4 +109,23 @@ bb:
ret void
}

@global = external addrspace(1) constant [16 x float], align 64

define float @issue160302(i1 %cond, ptr addrspace(5) %arg) {
; CHECK-LABEL: define float @issue160302(
; CHECK-SAME: i1 [[COND:%.*]], ptr addrspace(5) [[ARG:%.*]]) {
; CHECK-NEXT: [[AGG_TMP2_I4:%.*]] = alloca [16 x float], align 64, addrspace(5)
; CHECK-NEXT: [[SELECT_PTR:%.*]] = select i1 [[COND]], ptr addrspace(5) [[AGG_TMP2_I4]], ptr addrspace(5) [[ARG]]
; CHECK-NEXT: [[COND_I:%.*]] = load float, ptr addrspace(5) [[SELECT_PTR]], align 4
; CHECK-NEXT: ret float [[COND_I]]
;
%agg.tmp2.i4 = alloca [16 x float], align 64, addrspace(5)
call void @llvm.memcpy.p5.p1.i64(ptr addrspace(5) %agg.tmp2.i4, ptr addrspace(1) @global, i64 0, i1 false)
%m_Data.i14.i = getelementptr [16 x float], ptr addrspace(5) %agg.tmp2.i4, i32 0, i32 0
%gep = getelementptr [16 x float], ptr addrspace(5) %arg, i32 0, i32 0
%select.ptr = select i1 %cond, ptr addrspace(5) %m_Data.i14.i, ptr addrspace(5) %gep
%cond.i = load float, ptr addrspace(5) %select.ptr, align 4
ret float %cond.i
}

declare void @llvm.memcpy.p5.p4.i64(ptr addrspace(5) noalias writeonly captures(none), ptr addrspace(4) noalias readonly captures(none), i64, i1 immarg) #0
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