[clang] Classify vector types in __builtin_classify_type (#73299)

Author: tbaederr

clang/docs/ReleaseNotes.rst

@@ -225,8 +225,8 @@ Non-comprehensive list of changes in this release
   determined at runtime.
 * The ``__datasizeof`` keyword has been added. It is similar to ``sizeof``
   except that it returns the size of a type ignoring tail padding.
-* ``__builtin_classify_type()`` now classifies ``_BitInt`` values as the return value ``18``,
-  to match GCC 14's behavior.
+* ``__builtin_classify_type()`` now classifies ``_BitInt`` values as the return value ``18``
+  and vector types as return value ``19``, to match GCC 14's behavior.
 
 New Compiler Flags
 ------------------

clang/lib/AST/ExprConstShared.h

@@ -49,7 +49,8 @@ enum class GCCTypeClass {
   // literals.
   // Lang = 16,
   // OpaqueType = 17,
-  BitInt = 18
+  BitInt = 18,
+  Vector = 19
 };
 
 GCCTypeClass EvaluateBuiltinClassifyType(QualType T,

clang/lib/AST/ExprConstant.cpp

@@ -11615,16 +11615,18 @@ GCCTypeClass EvaluateBuiltinClassifyType(QualType T,
     return EvaluateBuiltinClassifyType(
         CanTy->castAs<AtomicType>()->getValueType(), LangOpts);
 
-  case Type::BlockPointer:
   case Type::Vector:
   case Type::ExtVector:
+    return GCCTypeClass::Vector;
+
+  case Type::BlockPointer:
   case Type::ConstantMatrix:
   case Type::ObjCObject:
   case Type::ObjCInterface:
   case Type::ObjCObjectPointer:
   case Type::Pipe:
-    // GCC classifies vectors as None. We follow its lead and classify all
-    // other types that don't fit into the regular classification the same way.
+    // Classify all other types that don't fit into the regular
+    // classification the same way.
     return GCCTypeClass::None;
 
   case Type::BitInt:

clang/test/Sema/builtin-classify-type.c

@@ -13,7 +13,7 @@ enum gcc_type_class {
   record_type_class, union_type_class,
   array_type_class, string_type_class,
   lang_type_class, opaque_type_class,
-  bitint_type_class
+  bitint_type_class, vector_type_class
 };
 
 void foo(void) {
@@ -67,8 +67,8 @@ void foo(void) {
   int a11[__builtin_classify_type(arr) == pointer_type_class ? 1 : -1];
   int a12[__builtin_classify_type("abc") == pointer_type_class ? 1 : -1];
   int a13[__builtin_classify_type(block) == no_type_class ? 1 : -1];
-  int a14[__builtin_classify_type(vec) == no_type_class ? 1 : -1];
-  int a15[__builtin_classify_type(evec) == no_type_class ? 1 : -1];
+  int a14[__builtin_classify_type(vec) == vector_type_class ? 1 : -1];
+  int a15[__builtin_classify_type(evec) == vector_type_class ? 1 : -1];
   int a16[__builtin_classify_type(atomic_i) == integer_type_class ? 1 : -1];
   int a17[__builtin_classify_type(atomic_d) == real_type_class ? 1 : -1];
   int a18[__builtin_classify_type(complex_i) == complex_type_class ? 1 : -1];

clang/test/SemaCXX/builtin-classify-type.cpp

@@ -13,7 +13,7 @@ enum gcc_type_class {
   record_type_class, union_type_class,
   array_type_class, string_type_class,
   lang_type_class, opaque_type_class,
-  bitint_type_class
+  bitint_type_class, vector_type_class
 };
 
 class cl {
@@ -62,8 +62,8 @@ void foo() {
   int a14[__builtin_classify_type(arr) == pointer_type_class ? 1 : -1];
   int a15[__builtin_classify_type("abc") == pointer_type_class ? 1 : -1];
   int a16[__builtin_classify_type(block) == no_type_class ? 1 : -1];
-  int a17[__builtin_classify_type(vec) == no_type_class ? 1 : -1];
-  int a18[__builtin_classify_type(evec) == no_type_class ? 1 : -1];
+  int a17[__builtin_classify_type(vec) == vector_type_class ? 1 : -1];
+  int a18[__builtin_classify_type(evec) == vector_type_class ? 1 : -1];
   int a19[__builtin_classify_type(atomic_i) == integer_type_class ? 1 : -1];
   int a20[__builtin_classify_type(atomic_d) == real_type_class ? 1 : -1];
   int a21[__builtin_classify_type(complex_i) == complex_type_class ? 1 : -1];