[clang] ef6172f - [clang] Apply lvalue conversions to __builtin_classify_type argument (#175627)

[via cfe-commits]

Author: keinflue
Date: 2026-03-24T10:19:43-04:00
New Revision: ef6172f32757aff6e4c4bb237ed3132d7ef24c12

URL: https://github.com/llvm/llvm-project/commit/ef6172f32757aff6e4c4bb237ed3132d7ef24c12
DIFF: https://github.com/llvm/llvm-project/commit/ef6172f32757aff6e4c4bb237ed3132d7ef24c12.diff

LOG: [clang] Apply lvalue conversions to __builtin_classify_type argument (#175627)

According to GCC documentation default argument promotion is applied to
the argument, which includes the function-to-pointer and
array-to-pointer lvalue conversions.

This also implies checking of the argument for placeholder types.

Fixes #175589.

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/lib/Sema/SemaChecking.cpp
    clang/test/SemaCXX/builtin-classify-type.cpp

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 7a369fb01bdd9..a8897c707b9e6 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -358,6 +358,7 @@ Bug Fixes in This Version
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+- Fix a crash when passing an unresolved overload set to ``__builtin_classify_type``. (#GH175589)
 - Fixed a crash when calling `__builtin_allow_sanitize_check` with no arguments. (#GH183927)
 
 Bug Fixes to Attribute Support

diff  --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 29add9d092e6b..00a664dfedbbc 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -3049,15 +3049,11 @@ Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID,
     if (BuiltinSetjmp(TheCall))
       return ExprError();
     break;
-  case Builtin::BI__builtin_classify_type:
-    if (checkArgCount(TheCall, 1))
-      return true;
-    TheCall->setType(Context.IntTy);
-    break;
   case Builtin::BI__builtin_complex:
     if (BuiltinComplex(TheCall))
       return ExprError();
     break;
+  case Builtin::BI__builtin_classify_type:
   case Builtin::BI__builtin_constant_p: {
     if (checkArgCount(TheCall, 1))
       return true;

diff  --git a/clang/test/SemaCXX/builtin-classify-type.cpp b/clang/test/SemaCXX/builtin-classify-type.cpp
index 6bae9cd6b1dc0..dde08f6d0a9ba 100644
--- a/clang/test/SemaCXX/builtin-classify-type.cpp
+++ b/clang/test/SemaCXX/builtin-classify-type.cpp
@@ -1,8 +1,6 @@
 // RUN: %clang_cc1 -fsyntax-only -verify -fblocks %s
 // RUN: %clang_cc1 -fsyntax-only -verify -fblocks %s -fexperimental-new-constant-interpreter
 
-// expected-no-diagnostics
-
 enum gcc_type_class {
   no_type_class = -1,
   void_type_class, integer_type_class, char_type_class,
@@ -71,3 +69,18 @@ void foo() {
   int a23[__builtin_classify_type(bitint) == bitint_type_class ? 1 : -1];
 }
 
+namespace GH175589 {
+  struct C {
+    template<class T>
+    void f() {}
+  };
+  // expected-error at +1 {{reference to overloaded function could not be resolved}}
+  int x1 = __builtin_classify_type(&C::f);
+
+  void g(int);
+  void g(double);
+  // expected-error at +3 {{reference to overloaded function could not be resolved}}
+  // expected-note at -3 {{possible target for call}}
+  // expected-note at -3 {{possible target for call}}
+  int x2 = __builtin_classify_type(g);
+}