https://github.com/efriedma-quic created https://github.com/llvm/llvm-project/pull/237634
Under the Microsoft ABI, a class with a user-provided constructor cannot be returned in a register. This check was fixed in 3ab4ae9e58c09 to also handle template constructors. That fix missed a special case of the special case: a deleted template constructor does not count as user-provided. Fixes #237188 >From 8d5ec133a66663e7a78466094022bb3ba363144f Mon Sep 17 00:00:00 2001 From: Eli Friedman <[email protected]> Date: Sat, 31 Oct 2026 14:03:28 -0700 Subject: [PATCH] [clang codegen] Fix MS ABI with deleted template constructor Under the Microsoft ABI, a class with a user-provided constructor cannot be returned in a register. This check was fixed in 3ab4ae9e58c09 to also handle template constructors. That fix missed a special case of the speecial case: a deleted template constructor does not count as user-provided. Fixes #237188 --- clang/docs/ReleaseNotes.md | 5 +++++ clang/lib/CodeGen/MicrosoftCXXABI.cpp | 3 ++- clang/test/CodeGen/arm64-microsoft-arguments.cpp | 13 +++++++++++++ 3 files changed, 20 insertions(+), 1 deletion(-) diff --git a/clang/docs/ReleaseNotes.md b/clang/docs/ReleaseNotes.md index 53d688d2e11e7c..a75ad9ca7fc74b 100644 --- a/clang/docs/ReleaseNotes.md +++ b/clang/docs/ReleaseNotes.md @@ -157,6 +157,11 @@ features cannot lower the translation-unit ABI level; accesses to these fields. `__attribute__((packed))` on the field or the enclosing record still reduces the alignment. (#GH208256) +- On Windows targets using Microsoft C++ ABI, fixed returning a class with + a deleted template constructor which should be returned in a register. + This affects the ABI of `std::strong_ordering` in some versions of the + Microsoft STL. (#GH237188) + ### AST Dumping Potentially Breaking Changes ### Clang Frontend Potentially Breaking Changes diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp index 86916104d13440..73c889d27c2a13 100644 --- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp +++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp @@ -1172,7 +1172,8 @@ static bool isTrivialForMSVC(const CXXRecordDecl *RD, QualType Ty, if (Ctor->isUserProvided()) return false; } else if (auto *Template = dyn_cast<FunctionTemplateDecl>(D)) { - if (isa<CXXConstructorDecl>(Template->getTemplatedDecl())) + if (isa<CXXConstructorDecl>(Template->getTemplatedDecl()) && + !Template->getTemplatedDecl()->isDeleted()) return false; } else if (auto *MethodDecl = dyn_cast<CXXMethodDecl>(D)) { if (MethodDecl->isCopyAssignmentOperator() && MethodDecl->isDeleted()) diff --git a/clang/test/CodeGen/arm64-microsoft-arguments.cpp b/clang/test/CodeGen/arm64-microsoft-arguments.cpp index 50a1b1f6bf5549..5a49eaf83c7cc3 100644 --- a/clang/test/CodeGen/arm64-microsoft-arguments.cpp +++ b/clang/test/CodeGen/arm64-microsoft-arguments.cpp @@ -216,3 +216,16 @@ S12 f12() { S12 x((int*)0); return func12(x); } + +// GH237188 +// Ignore deleted template constructor +// CHECK: define dso_local i32 @"?f13@@YA?AUS13@@PEAU1@@Z"(ptr noundef {{.*}}) +// CHECK: call i32 @"?func13@@YA?AUS13@@U1@@Z"(i32 {{.*}}) +struct S13 { + template<typename T> S13(T*) = delete; + int x; +}; +S13 func13(S13 x); +S13 f13(S13 *p) { + return func13(*p); +} _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
