https://github.com/IvyXu420 updated https://github.com/llvm/llvm-project/pull/235265
>From 8c565c58747c72691a15110575d147a27b84fb90 Mon Sep 17 00:00:00 2001 From: Ivy Xu <[email protected]> Date: Sat, 24 Oct 2026 15:40:04 +0800 Subject: [PATCH 1/4] Fix `IsStructurallyEquivalent` for constexpr BitField --- clang/lib/AST/ASTStructuralEquivalence.cpp | 11 ++++++----- clang/test/C/C23/n3037.c | 13 +++++++++++++ 2 files changed, 19 insertions(+), 5 deletions(-) diff --git a/clang/lib/AST/ASTStructuralEquivalence.cpp b/clang/lib/AST/ASTStructuralEquivalence.cpp index 029e33ae0db760..f6fa067810550f 100644 --- a/clang/lib/AST/ASTStructuralEquivalence.cpp +++ b/clang/lib/AST/ASTStructuralEquivalence.cpp @@ -1664,13 +1664,13 @@ static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context, return false; } - if ((Field1->isBitField() || Field2->isBitField()) && - !IsStructurallyEquivalent(Context, Field1->getBitWidth(), - Field2->getBitWidth())) { + if ((Field1->isBitField() || Field2->isBitField())) { // Two bit-fields can be structurally unequivalent but still be okay for // the purposes of C where they simply need to have the same values, not // the same token sequences. - bool Diagnose = true; + bool Diagnose = false; + if (!IsStructurallyEquivalent(Context, Field1->getBitWidth(), Field2->getBitWidth())) + Diagnose = true; if (Context.LangOpts.C23 && Field1->isBitField() && Field2->isBitField()) Diagnose = Field1->getBitWidthValue() != Field2->getBitWidthValue(); @@ -1695,7 +1695,8 @@ static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context, DiagNote(Field2, &StructuralEquivalenceContext::Diag2); DiagNote(Field1, &StructuralEquivalenceContext::Diag1); } - return false; + if (Diagnose) + return false; } return true; diff --git a/clang/test/C/C23/n3037.c b/clang/test/C/C23/n3037.c index 8dd46ef69b4146..97320820a3eeba 100644 --- a/clang/test/C/C23/n3037.c +++ b/clang/test/C/C23/n3037.c @@ -948,3 +948,16 @@ struct GH199417_3 { // it would be better to print the original type. } a; // c23-note {{field 'a' has type 'int' here}} }; + +#if __STDC_VERSION__ >= 202311L +constexpr int n = 1; +constexpr int m = 2; +struct GH232748 { + struct S { int i : n; } s1; // c23-note {{bit-field 'i' has bit-width 1 here}} + struct S { int i : m; } s2; // c23-error {{type 'struct S' has incompatible definitions}} + // c23-note@-1 {{bit-field 'i' has bit-width 2 here}} + + struct M { int i : n; } m1; + struct M { int i : n; } m2; +}; +#endif >From 1795d565c43e96c79a783e5722f9014499827e98 Mon Sep 17 00:00:00 2001 From: Ivy Xu <[email protected]> Date: Sat, 24 Oct 2026 17:06:31 +0800 Subject: [PATCH 2/4] Fix code formatting --- clang/lib/AST/ASTStructuralEquivalence.cpp | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/clang/lib/AST/ASTStructuralEquivalence.cpp b/clang/lib/AST/ASTStructuralEquivalence.cpp index f6fa067810550f..cd0b03c5cc356d 100644 --- a/clang/lib/AST/ASTStructuralEquivalence.cpp +++ b/clang/lib/AST/ASTStructuralEquivalence.cpp @@ -1669,8 +1669,9 @@ static bool IsStructurallyEquivalent(StructuralEquivalenceContext &Context, // the purposes of C where they simply need to have the same values, not // the same token sequences. bool Diagnose = false; - if (!IsStructurallyEquivalent(Context, Field1->getBitWidth(), Field2->getBitWidth())) - Diagnose = true; + if (!IsStructurallyEquivalent(Context, Field1->getBitWidth(), + Field2->getBitWidth())) + Diagnose = true; if (Context.LangOpts.C23 && Field1->isBitField() && Field2->isBitField()) Diagnose = Field1->getBitWidthValue() != Field2->getBitWidthValue(); >From 45563115edda1d2ea93670c4f244b481908d4ca6 Mon Sep 17 00:00:00 2001 From: Ivy Xu <[email protected]> Date: Sun, 25 Oct 2026 22:15:08 +0800 Subject: [PATCH 3/4] Add release note --- clang/docs/ReleaseNotes.md | 1 + 1 file changed, 1 insertion(+) diff --git a/clang/docs/ReleaseNotes.md b/clang/docs/ReleaseNotes.md index 3f0c48cf36644d..bd588fef3eee6b 100644 --- a/clang/docs/ReleaseNotes.md +++ b/clang/docs/ReleaseNotes.md @@ -733,6 +733,7 @@ features cannot lower the translation-unit ABI level; - Fixed assertion failures caused by stale linkage information when an extern variable or function declaration is merged with a preceding static declaration. (#GH204759, #GH204754) - Fixed a crash due to typo correction mishandling custom keywords `_virtual_inheritance` and `_multiple_inheritance` in `-fms-compatibility` mode. (#GH228003) - Clang no longer treats a file-scope `thread_local` declaration without an initializer as a tentative definition in C23 mode. As specified by C23 6.9.3, such a declaration is a definition, so declaring the same variable more that once is now diagnosed as a redefinition. (#GH217636) +- Fixed acceptance of redefinition of a struct with different bit-field width in C23 mode. (#GH232748) - Fixed an assertion failure on use of an uninitialized token in dependency directives lexing in clang-scan-deps. - Fixed auto type inference being rejected when the initializer is a bit-field. (#GH226280) - Fixed failed assertion when creating a compound literal with erroneous initializer at file scope. (#GH229888) >From 57166096c1ff702255c352fef927dd5a220a1d13 Mon Sep 17 00:00:00 2001 From: Ivy Xu <[email protected]> Date: Mon, 26 Oct 2026 21:53:23 +0800 Subject: [PATCH 4/4] address review --- clang/test/C/C23/n3037.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/clang/test/C/C23/n3037.c b/clang/test/C/C23/n3037.c index 97320820a3eeba..73b5ec79559ec2 100644 --- a/clang/test/C/C23/n3037.c +++ b/clang/test/C/C23/n3037.c @@ -949,15 +949,17 @@ struct GH199417_3 { } a; // c23-note {{field 'a' has type 'int' here}} }; -#if __STDC_VERSION__ >= 202311L -constexpr int n = 1; -constexpr int m = 2; +constexpr int n = 1; // c17-error {{unknown type name 'constexpr'}} +constexpr int o = 1; // c17-error {{unknown type name 'constexpr'}} +constexpr int m = 2; // c17-error {{unknown type name 'constexpr'}} struct GH232748 { struct S { int i : n; } s1; // c23-note {{bit-field 'i' has bit-width 1 here}} + // c17-note@-1 {{previous definition is here}} struct S { int i : m; } s2; // c23-error {{type 'struct S' has incompatible definitions}} // c23-note@-1 {{bit-field 'i' has bit-width 2 here}} - - struct M { int i : n; } m1; - struct M { int i : n; } m2; + // c17-error@-2 {{redefinition of 'S'}} + struct M { int i : n; } m2; // c17-note {{previous definition is here}} + struct M { int i : n; } m1; // c17-error {{redefinition of 'M'}} + struct N { int i : o; } n1; // c17-note {{previous definition is here}} + struct N { int i : n; } n2; // c17-error {{redefinition of 'N}} }; -#endif _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
