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[clang][bytecode] Fail on reads from constexpr-unknown pointers #164996

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Merged
merged 1 commit into from
Oct 27, 2025
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[clang][bytecode] Fail on reads from constexpr-unknown pointers #164996

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2 changes: 2 additions & 0 deletions clang/lib/AST/ByteCode/Interp.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -832,6 +832,8 @@ bool CheckLoad(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
return false;
if (!CheckVolatile(S, OpPC, Ptr, AK))
return false;
if (!Ptr.isConst() && !S.inConstantContext() && isConstexprUnknown(Ptr))
return false;
return true;
}

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15 changes: 15 additions & 0 deletions clang/test/AST/ByteCode/codegen-cxx20.cpp
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@@ -0,0 +1,15 @@
// RUN: %clang_cc1 -triple x86_64-linux -emit-llvm -o - %s -fcxx-exceptions | FileCheck %s
// RUN: %clang_cc1 -triple x86_64-linux -emit-llvm -o - %s -fcxx-exceptions -fexperimental-new-constant-interpreter | FileCheck %s


/// The read from a used to succeed, causing the entire if statement to vanish.
extern void e();
int somefunc() {
auto foo = [a = false]() mutable {
if (a)
e();
};
foo();
}

// CHECK: call void @_Z1ev()