llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Eli Friedman (efriedma-quic) <details> <summary>Changes</summary> Manual backport of 6a60f18997d62b0e2842a921fcb6beb3e52ed823 --- Full diff: https://github.com/llvm/llvm-project/pull/149402.diff 3 Files Affected: - (modified) clang/lib/AST/ExprConstant.cpp (+7-4) - (modified) clang/test/SemaCXX/constant-expression-p2280r4.cpp (+26) - (modified) clang/test/SemaCXX/constexpr-never-constant.cpp (+7) ``````````diff diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index 1b33b6706e204..d7b1173283c57 100644 --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -4441,7 +4441,8 @@ static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E, } } else if (!IsAccess) { return CompleteObject(LVal.getLValueBase(), nullptr, BaseType); - } else if (IsConstant && Info.checkingPotentialConstantExpression() && + } else if ((IsConstant || BaseType->isReferenceType()) && + Info.checkingPotentialConstantExpression() && BaseType->isLiteralType(Info.Ctx) && !VD->hasDefinition()) { // This variable might end up being constexpr. Don't diagnose it yet. } else if (IsConstant) { @@ -4478,9 +4479,11 @@ static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E, // a null BaseVal. Any constexpr-unknown variable seen here is an error: // we can't access a constexpr-unknown object. if (!BaseVal) { - Info.FFDiag(E, diag::note_constexpr_access_unknown_variable, 1) - << AK << VD; - Info.Note(VD->getLocation(), diag::note_declared_at); + if (!Info.checkingPotentialConstantExpression()) { + Info.FFDiag(E, diag::note_constexpr_access_unknown_variable, 1) + << AK << VD; + Info.Note(VD->getLocation(), diag::note_declared_at); + } return CompleteObject(); } } else if (DynamicAllocLValue DA = LVal.Base.dyn_cast<DynamicAllocLValue>()) { diff --git a/clang/test/SemaCXX/constant-expression-p2280r4.cpp b/clang/test/SemaCXX/constant-expression-p2280r4.cpp index 03fea91169787..16f5f823d26c1 100644 --- a/clang/test/SemaCXX/constant-expression-p2280r4.cpp +++ b/clang/test/SemaCXX/constant-expression-p2280r4.cpp @@ -357,3 +357,29 @@ namespace pointer_comparisons { static_assert(!f4()); // expected-error {{static assertion expression is not an integral constant expression}} \ // expected-note {{in call to 'f4()'}} } + +namespace GH149188 { +namespace enable_if_1 { + template <__SIZE_TYPE__ N> + constexpr void foo(const char (&Str)[N]) + __attribute((enable_if(__builtin_strlen(Str), ""))) {} + + void x() { + foo("1234"); + } +} + +namespace enable_if_2 { + constexpr const char (&f())[]; + extern const char (&Str)[]; + constexpr int foo() + __attribute((enable_if(__builtin_strlen(Str), ""))) + {return __builtin_strlen(Str);} + + constexpr const char (&f())[] {return "a";} + constexpr const char (&Str)[] = f(); + void x() { + constexpr int x = foo(); + } +} +} diff --git a/clang/test/SemaCXX/constexpr-never-constant.cpp b/clang/test/SemaCXX/constexpr-never-constant.cpp index 307810ee263dd..5756bb647ce88 100644 --- a/clang/test/SemaCXX/constexpr-never-constant.cpp +++ b/clang/test/SemaCXX/constexpr-never-constant.cpp @@ -24,3 +24,10 @@ constexpr void other_func() { throw 12; } + +namespace GH149041 { + // Make sure these don't trigger the diagnostic. + extern const bool& b; + constexpr bool fun1() { return b; } + constexpr bool fun2(const bool& b) { return b; } +} `````````` </details> https://github.com/llvm/llvm-project/pull/149402 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits