llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang-codegen Author: Yingwei Zheng (dtcxzyw) <details> <summary>Changes</summary> After https://github.com/llvm/llvm-project/pull/95474, unknown references are valid in constant expressions. However, constexpr-unknown values are not allowed in CodeGen. This patch bails out on constexpr-unknown values to ensure the load of reference is emitted. Close https://github.com/llvm/llvm-project/issues/127475 --- Full diff: https://github.com/llvm/llvm-project/pull/127525.diff 2 Files Affected: - (modified) clang/lib/CodeGen/CGExprConstant.cpp (+4-2) - (added) clang/test/CodeGenCXX/cxx23-p2280r4.cpp (+15) ``````````diff diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp index ee5874b26f534..075f3f435ad74 100644 --- a/clang/lib/CodeGen/CGExprConstant.cpp +++ b/clang/lib/CodeGen/CGExprConstant.cpp @@ -1883,8 +1883,10 @@ llvm::Constant *ConstantEmitter::tryEmitPrivateForVarInit(const VarDecl &D) { // Try to emit the initializer. Note that this can allow some things that // are not allowed by tryEmitPrivateForMemory alone. - if (APValue *value = D.evaluateValue()) - return tryEmitPrivateForMemory(*value, destType); + if (APValue *value = D.evaluateValue()) { + if (!value->allowConstexprUnknown()) + return tryEmitPrivateForMemory(*value, destType); + } return nullptr; } diff --git a/clang/test/CodeGenCXX/cxx23-p2280r4.cpp b/clang/test/CodeGenCXX/cxx23-p2280r4.cpp new file mode 100644 index 0000000000000..d5409be451df0 --- /dev/null +++ b/clang/test/CodeGenCXX/cxx23-p2280r4.cpp @@ -0,0 +1,15 @@ +// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++23 %s -emit-llvm -o - | FileCheck %s +// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++20 %s -emit-llvm -o - | FileCheck %s +// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++17 %s -emit-llvm -o - | FileCheck %s + +extern int& s; + +// CHECK: @_Z4testv() +// CHECK-NEXT: entry: +// CHECK-NEXT: [[I:%.*]] = alloca ptr, align {{.*}} +// CHECK-NEXT: [[X:%.*]] = load ptr, ptr @s, align {{.*}} +// CHECK-NEXT: store ptr [[X]], ptr [[I]], align {{.*}} +int& test() { + auto &i = s; + return i; +} `````````` </details> https://github.com/llvm/llvm-project/pull/127525 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
