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[Clang] Fix crash on void{} #147514

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Merged
merged 3 commits into from
Jul 8, 2025
Merged

[Clang] Fix crash on void{} #147514

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17b5932
[Clang] Fix crash on `void{}`
cor3ntin Jul 8, 2025
69a6547
improve test
cor3ntin Jul 8, 2025
6ca3ffa
add triple
cor3ntin Jul 8, 2025
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4 changes: 3 additions & 1 deletion clang/lib/CodeGen/CGExprScalar.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2114,8 +2114,10 @@ static int getAsInt32(llvm::ConstantInt *C, llvm::Type *I32Ty) {
Value *ScalarExprEmitter::VisitInitListExpr(InitListExpr *E) {
bool Ignore = TestAndClearIgnoreResultAssign();
(void)Ignore;
assert (Ignore == false && "init list ignored");
unsigned NumInitElements = E->getNumInits();
assert(Ignore == false ||
(NumInitElements == 0 && E->getType()->isVoidType()) &&
"init list ignored");
Comment on lines +2118 to +2120
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This new assert formulation raises a warning in gcc -Wall: https://godbolt.org/z/G8v1zqE4Y
And the grouping of the comment "init list ignored" to only the second condition seems unintended or misleading. Could we revise this?

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See #158635


// HLSL initialization lists in the AST are an expansion which can contain
// side-effecting expressions wrapped in opaque value expressions. To properly
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14 changes: 13 additions & 1 deletion clang/test/CodeGenCXX/cxx0x-initializer-scalars.cpp
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@@ -1,7 +1,19 @@
// RUN: %clang_cc1 -std=c++11 -emit-llvm -o - %s | FileCheck %s
// RUN: %clang_cc1 -std=c++11 -triple x86_64-linux -emit-llvm -o - %s | FileCheck %s

void f()
{
// CHECK: store i32 0
int i{};
}


namespace GH116440 {
void f() {
void{};
void();
}
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Can you add check-lines to this one?

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What do you want me to check? noting is emitted

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Just the function header then CHECK-NEXT: ret void confirms that it actually does nothing/makes it through codegen without going sideways.

So:

// CHECK: define{{.*}} void @{{.*}}GH116440{{.*}}()
// CHECK-NEXT: {{.*}}:
// CHECK-NEXT: ret void

That should work on both windows and itanium manglers, though be more specific on the function name if this test uses a triple.


// CHECK: define{{.*}} void @_ZN8GH1164401fEv()
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There is no target-triple on this test, so this will fail in windows mode. You can try running it with -triple x86_64-windows-pc to see what I mean.

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oups!

// CHECK-NEXT: entry
// CHECK-NEXT: ret void
}