https://github.com/akash-manna-sky updated https://github.com/llvm/llvm-project/pull/219767
>From 6ee72a2b6e324ba6a1265e25c0670ac956546fa2 Mon Sep 17 00:00:00 2001 From: Akash Manna <[email protected]> Date: Sun, 30 Aug 2026 10:57:14 +0530 Subject: [PATCH 1/2] [clang] Reject references to vector types in __builtin_vectorelements Fixes #216997 CheckUnaryExprOrTypeTraitOperand looks through reference types for all trait kinds before dispatching to the __builtin_vectorelements check, so a reference to a vector type passed Sema while the expression kept the reference as its argument type. Constant evaluation and codegen require that type to be a vector type and assert otherwise. Check the __builtin_vectorelements operand before the reference is looked through, so it is diagnosed like any other non-vector type. --- clang/docs/ReleaseNotes.md | 2 ++ clang/lib/Sema/SemaExpr.cpp | 10 ++++++---- clang/test/SemaCXX/GH216997.cpp | 32 ++++++++++++++++++++++++++++++++ 3 files changed, 40 insertions(+), 4 deletions(-) create mode 100644 clang/test/SemaCXX/GH216997.cpp diff --git a/clang/docs/ReleaseNotes.md b/clang/docs/ReleaseNotes.md index bdbabf2cd98d0..a80bba3d99003 100644 --- a/clang/docs/ReleaseNotes.md +++ b/clang/docs/ReleaseNotes.md @@ -457,6 +457,8 @@ features cannot lower the translation-unit ABI level; such as when the call is used as an `auto` non-type template argument. - Fixed a crash in ``__builtin_dump_struct`` when ``-Werror`` promotes format warnings to errors. (#GH211943) +- Fixed a crash when `__builtin_vectorelements` is applied to a reference to a + vector type; this is now diagnosed as an invalid argument type. (#GH216997) #### Bug Fixes to Attribute Support diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp index 34f6ccdbc2fe6..348d3e9ef33c0 100644 --- a/clang/lib/Sema/SemaExpr.cpp +++ b/clang/lib/Sema/SemaExpr.cpp @@ -4742,6 +4742,12 @@ bool Sema::CheckUnaryExprOrTypeTraitOperand(QualType ExprType, if (ExprType->isDependentType()) return false; + // A reference to a vector type is not a vector type; check this before the + // reference is looked through below. + if (ExprKind == UETT_VectorElements) + return CheckVectorElementsTraitOperandType(*this, ExprType, OpLoc, + ExprRange); + // C++ [expr.sizeof]p2: // When applied to a reference or a reference type, the result // is the size of the referenced type. @@ -4767,10 +4773,6 @@ bool Sema::CheckUnaryExprOrTypeTraitOperand(QualType ExprType, if (ExprKind == UETT_VecStep) return CheckVecStepTraitOperandType(*this, ExprType, OpLoc, ExprRange); - if (ExprKind == UETT_VectorElements) - return CheckVectorElementsTraitOperandType(*this, ExprType, OpLoc, - ExprRange); - if (ExprKind == UETT_PtrAuthTypeDiscriminator) return checkPtrAuthTypeDiscriminatorOperandType(*this, ExprType, OpLoc, ExprRange); diff --git a/clang/test/SemaCXX/GH216997.cpp b/clang/test/SemaCXX/GH216997.cpp new file mode 100644 index 0000000000000..407c618421484 --- /dev/null +++ b/clang/test/SemaCXX/GH216997.cpp @@ -0,0 +1,32 @@ +// RUN: %clang_cc1 -triple x86_64 -std=c++20 -fsyntax-only -verify %s +// RUN: %clang_cc1 -triple x86_64 -std=c++20 -fsyntax-only -verify -fexperimental-new-constant-interpreter %s + +// Reproducer from GH216997. +using vec __attribute__((vector_size(16))) = int &bar; // expected-error {{type-id cannot have a name}} +int baz = __builtin_vectorelements(vec); // expected-error {{argument to __builtin_vectorelements must be of vector type}} + +using vec_ref __attribute__((vector_size(16))) = int &; +static_assert(sizeof(vec_ref) == 16, ""); +int a = __builtin_vectorelements(vec_ref); // expected-error {{argument to __builtin_vectorelements must be of vector type}} + +typedef int veci4 __attribute__((vector_size(16))); +int b = __builtin_vectorelements(veci4 &); // expected-error {{argument to __builtin_vectorelements must be of vector type}} +int c = __builtin_vectorelements(veci4 &&); // expected-error {{argument to __builtin_vectorelements must be of vector type}} +int d = __builtin_vectorelements(const veci4 &); // expected-error {{argument to __builtin_vectorelements must be of vector type}} + +veci4 v; +int e = __builtin_vectorelements(decltype((v))); // expected-error {{argument to __builtin_vectorelements must be of vector type}} + +template <typename T> +int f() { + return __builtin_vectorelements(T); // expected-error {{argument to __builtin_vectorelements must be of vector type}} +} +int g = f<veci4>(); +int h = f<veci4 &>(); // expected-note {{in instantiation of function template specialization}} + +void ok(veci4 &r, veci4 &&rr) { + (void)__builtin_vectorelements(r); + (void)__builtin_vectorelements(rr); + (void)__builtin_vectorelements(const veci4); + (void)__builtin_vectorelements(decltype(v)); +} >From eeacd507c7beb32a005633286e0d5fbef1d77b70 Mon Sep 17 00:00:00 2001 From: Akash Manna <[email protected]> Date: Sun, 30 Aug 2026 11:02:56 +0530 Subject: [PATCH 2/2] Fix assertion failure for __builtin_vectorelements with vector type references --- clang/docs/ReleaseNotes.md | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/clang/docs/ReleaseNotes.md b/clang/docs/ReleaseNotes.md index a80bba3d99003..ba737310919c4 100644 --- a/clang/docs/ReleaseNotes.md +++ b/clang/docs/ReleaseNotes.md @@ -457,8 +457,9 @@ features cannot lower the translation-unit ABI level; such as when the call is used as an `auto` non-type template argument. - Fixed a crash in ``__builtin_dump_struct`` when ``-Werror`` promotes format warnings to errors. (#GH211943) -- Fixed a crash when `__builtin_vectorelements` is applied to a reference to a - vector type; this is now diagnosed as an invalid argument type. (#GH216997) +- Fixed an assertion failure when `__builtin_vectorelements` is applied to a + reference to a vector type; this is now diagnosed as an invalid argument type. + (#GH216997) #### Bug Fixes to Attribute Support _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
