[libc-commits] [libc] 8ef0c50 - [libc] Fix problem with older compilers that do not have __has_builtin. (#150264)

[via libc-commits]

Author: lntue
Date: 2025-07-23T13:16:09-04:00
New Revision: 8ef0c50ecac8f1e707c02bee855f43eda114f8db

URL: https://github.com/llvm/llvm-project/commit/8ef0c50ecac8f1e707c02bee855f43eda114f8db
DIFF: https://github.com/llvm/llvm-project/commit/8ef0c50ecac8f1e707c02bee855f43eda114f8db.diff

LOG: [libc] Fix problem with older compilers that do not have __has_builtin. (#150264)

Fixing bot failures:
https://lab.llvm.org/buildbot/#/builders/10/builds/10025

Added: 
    

Modified: 
    libc/src/__support/CPP/type_traits/is_constant_evaluated.h
    libc/src/__support/macros/attributes.h

Removed: 
    


################################################################################
diff  --git a/libc/src/__support/CPP/type_traits/is_constant_evaluated.h b/libc/src/__support/CPP/type_traits/is_constant_evaluated.h
index 0bb2d0806cb0d..9339af46d6762 100644
--- a/libc/src/__support/CPP/type_traits/is_constant_evaluated.h
+++ b/libc/src/__support/CPP/type_traits/is_constant_evaluated.h
@@ -15,7 +15,11 @@ namespace LIBC_NAMESPACE_DECL {
 namespace cpp {
 
 LIBC_INLINE constexpr bool is_constant_evaluated() {
+#if LIBC_HAS_BUILTIN(__builtin_is_constant_evaluated)
   return __builtin_is_constant_evaluated();
+#else
+  return false;
+#endif
 }
 
 } // namespace cpp

diff  --git a/libc/src/__support/macros/attributes.h b/libc/src/__support/macros/attributes.h
index c6474673de85a..62b0f7c3d6155 100644
--- a/libc/src/__support/macros/attributes.h
+++ b/libc/src/__support/macros/attributes.h
@@ -48,4 +48,10 @@
 #define LIBC_PREFERED_TYPE(TYPE)
 #endif
 
+#ifndef __has_builtin
+#define LIBC_HAS_BUILTIN(X) 0
+#else
+#define LIBC_HAS_BUILTIN(X) __has_builtin(X)
+#endif
+
 #endif // LLVM_LIBC_SRC___SUPPORT_MACROS_ATTRIBUTES_H