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[CodeGen][GC] Initialize roots with Constant::getNullValue() instead of ConstantPointerNull::get() (#199367)

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Fixes #199219
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isuckatcs 2026-05-25 02:16:17 +02:00 committed by GitHub
parent ab1745439c
commit 11f0e7768b
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GPG key ID: B5690EEEBB952194
2 changed files with 28 additions and 3 deletions
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5
llvm/lib/CodeGen/GCRootLowering.cpp
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@ -177,9 +177,8 @@ static bool InsertRootInitializers(Function &F, ArrayRef<AllocaInst *> Roots) {
for (AllocaInst *Root : Roots)
if (!InitedRoots.count(Root)) {
new StoreInst(
ConstantPointerNull::get(cast<PointerType>(Root->getAllocatedType())),
Root, std::next(Root->getIterator()));
new StoreInst(Constant::getNullValue(Root->getAllocatedType()), Root,
std::next(Root->getIterator()));
MadeChange = true;
}

26
llvm/test/CodeGen/Generic/gc-lowering.ll
View file

@ -60,3 +60,29 @@ define void @no_gc() {
;
ret void
}
@metadata = constant i32 0
define void @non_ptr_alloca_root() gc "shadow-stack" {
; CHECK-LABEL: define void @non_ptr_alloca_root() gc "shadow-stack" {
; CHECK-NEXT: entry:
; CHECK-NEXT: %A = alloca double, align 8
; CHECK-NEXT: store double 0.000000e+00, ptr %A, align 8
; CHECK-NEXT: %B = alloca { double, double }, align 8
; CHECK-NEXT: store { double, double } zeroinitializer, ptr %B, align 8
; CHECK-NEXT: call void @llvm.gcroot(ptr %A, ptr @metadata)
; CHECK-NEXT: call void @llvm.gcroot(ptr %B, ptr @metadata)
; CHECK-NEXT: ret void
; CHECK-NEXT: }
entry:
%A = alloca double
%B = alloca { double, double }
;; ptr A;
call void @llvm.gcroot(ptr %A, ptr @metadata)
;; ptr B;
call void @llvm.gcroot(ptr %B, ptr @metadata)
ret void
}