llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Oleksandr T. (a-tarasyuk) <details> <summary>Changes</summary> Fixes #<!-- -->92583 --- Full diff: https://github.com/llvm/llvm-project/pull/94123.diff 3 Files Affected: - (modified) clang/lib/Sema/SemaDeclCXX.cpp (+22-12) - (modified) clang/test/SemaCXX/constant-expression-cxx14.cpp (+1-1) - (added) clang/test/SemaCXX/constexpr-return-non-void-cxx2b.cpp (+7) ``````````diff diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp index 631fd4e354927..d4401a427282c 100644 --- a/clang/lib/Sema/SemaDeclCXX.cpp +++ b/clang/lib/Sema/SemaDeclCXX.cpp @@ -1806,6 +1806,7 @@ static unsigned getRecordDiagFromTagKind(TagTypeKind Tag) { static bool CheckConstexprFunctionBody(Sema &SemaRef, const FunctionDecl *Dcl, Stmt *Body, Sema::CheckConstexprKind Kind); +static bool CheckConstexprMissingReturn(Sema &SemaRef, const FunctionDecl *Dcl); // Check whether a function declaration satisfies the requirements of a // constexpr function definition or a constexpr constructor definition. If so, @@ -2411,20 +2412,9 @@ static bool CheckConstexprFunctionBody(Sema &SemaRef, const FunctionDecl *Dcl, } } else { if (ReturnStmts.empty()) { - // C++1y doesn't require constexpr functions to contain a 'return' - // statement. We still do, unless the return type might be void, because - // otherwise if there's no return statement, the function cannot - // be used in a core constant expression. - bool OK = SemaRef.getLangOpts().CPlusPlus14 && - (Dcl->getReturnType()->isVoidType() || - Dcl->getReturnType()->isDependentType()); switch (Kind) { case Sema::CheckConstexprKind::Diagnose: - SemaRef.Diag(Dcl->getLocation(), - OK ? diag::warn_cxx11_compat_constexpr_body_no_return - : diag::err_constexpr_body_no_return) - << Dcl->isConsteval(); - if (!OK) + if (!CheckConstexprMissingReturn(SemaRef, Dcl)) return false; break; @@ -2487,6 +2477,26 @@ static bool CheckConstexprFunctionBody(Sema &SemaRef, const FunctionDecl *Dcl, return true; } +static bool CheckConstexprMissingReturn(Sema &SemaRef, + const FunctionDecl *Dcl) { + bool IsVoidOrDependentType = Dcl->getReturnType()->isVoidType() || + Dcl->getReturnType()->isDependentType(); + + if (SemaRef.getLangOpts().CPlusPlus23 && !IsVoidOrDependentType) + return true; + + // C++1y doesn't require constexpr functions to contain a 'return' + // statement. We still do, unless the return type might be void, because + // otherwise if there's no return statement, the function cannot + // be used in a core constant expression. + bool OK = SemaRef.getLangOpts().CPlusPlus14 && IsVoidOrDependentType; + SemaRef.Diag(Dcl->getLocation(), + OK ? diag::warn_cxx11_compat_constexpr_body_no_return + : diag::err_constexpr_body_no_return) + << Dcl->isConsteval(); + return OK; +} + bool Sema::CheckImmediateEscalatingFunctionDefinition( FunctionDecl *FD, const sema::FunctionScopeInfo *FSI) { if (!getLangOpts().CPlusPlus20 || !FD->isImmediateEscalating()) diff --git a/clang/test/SemaCXX/constant-expression-cxx14.cpp b/clang/test/SemaCXX/constant-expression-cxx14.cpp index 80a7a2dd31531..70ab5dcd357c1 100644 --- a/clang/test/SemaCXX/constant-expression-cxx14.cpp +++ b/clang/test/SemaCXX/constant-expression-cxx14.cpp @@ -82,7 +82,7 @@ constexpr void k() { // If the return type is not 'void', no return statements => never a constant // expression, so still diagnose that case. -[[noreturn]] constexpr int fn() { // expected-error {{no return statement in constexpr function}} +[[noreturn]] constexpr int fn() { // cxx14_20-error {{no return statement in constexpr function}} fn(); } diff --git a/clang/test/SemaCXX/constexpr-return-non-void-cxx2b.cpp b/clang/test/SemaCXX/constexpr-return-non-void-cxx2b.cpp new file mode 100644 index 0000000000000..91a8bb656b317 --- /dev/null +++ b/clang/test/SemaCXX/constexpr-return-non-void-cxx2b.cpp @@ -0,0 +1,7 @@ +// RUN: %clang_cc1 -Wno-return-type -std=c++23 -fsyntax-only -verify %s +// expected-no-diagnostics +constexpr int f() { } +static_assert(__is_same(decltype([] constexpr -> int { }( )), int)); + +consteval int g() { } +static_assert(__is_same(decltype([] consteval -> int { }( )), int)); `````````` </details> https://github.com/llvm/llvm-project/pull/94123 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
