[gcc(refs/users/aoliva/heads/testme)] libsupc++: try cxa_thread_atexit_impl at runtime

[Alexandre Oliva <aoliva@gcc.gnu.org>]

https://gcc.gnu.org/g:e07716aa13d7c3e81cb0ff5c5031ddcf8278b63a

commit e07716aa13d7c3e81cb0ff5c5031ddcf8278b63a
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Wed Nov 8 20:34:20 2023 -0300

    libsupc++: try cxa_thread_atexit_impl at runtime

Diff:
---
 libstdc++-v3/include/bits/stl_bvector.h | 50 ++++-----------------------------
 1 file changed, 6 insertions(+), 44 deletions(-)

diff --git a/libstdc++-v3/include/bits/stl_bvector.h b/libstdc++-v3/include/bits/stl_bvector.h
index 81b31684645..97a45582e69 100644
--- a/libstdc++-v3/include/bits/stl_bvector.h
+++ b/libstdc++-v3/include/bits/stl_bvector.h
@@ -56,6 +56,10 @@
 #ifndef _STL_BVECTOR_H
 #define _STL_BVECTOR_H 1
 
+#ifndef _GLIBCXX_ALWAYS_INLINE
+#define _GLIBCXX_ALWAYS_INLINE inline __attribute__((__always_inline__))
+#endif
+
 #if __cplusplus >= 201103L
 #include <initializer_list>
 #include <bits/functional_hash.h>
@@ -177,53 +181,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
     _Bit_type * _M_p;
     unsigned int _M_offset;
 
-#if __OPTIMIZE__ && !__GLIBCXX_DISABLE_ASSUMPTIONS
-// If the assumption (EXPR) fails, invoke undefined behavior, so that
-// the test and the failure block gets optimized out, but the compiler
-// still recalls that (expr) can be taken for granted.  Use this only
-// for expressions that are simple and explicit enough that the
-// compiler can optimize based on them.  When not optimizing, the
-// expression is still compiled, but it's never executed.
-#if 0 /* ??? */ && __cpp_lib_is_constant_evaluated
-#define __GLIBCXX_BUILTIN_ASSUME(expr)		\
-    do						\
-      if (std::is_constant_evaluated ())	\
-	static_assert(expr);			\
-      else if (!(expr))				\
-	{					\
-	  void **__assert_failed = 0;		\
-	  *__assert_failed = 0;			\
-	  __builtin_unreachable ();		\
-	}					\
-    while (0)
-#else
-#define __GLIBCXX_BUILTIN_ASSUME(expr)		\
-    do						\
-      if (!(expr))				\
-	{					\
-	  void **__assert_failed = 0;		\
-	  *__assert_failed = 0;			\
-	  __builtin_unreachable ();		\
-	}					\
-    while (0)
-#endif
-#else
-#define __GLIBCXX_BUILTIN_ASSUME(expr)		\
-    (void)(false && (expr))
-#endif
-
-    _GLIBCXX20_CONSTEXPR
-    bool
-    _M_normalized_p() const
-    {
-      return (_M_offset < unsigned(_S_word_bit));
-    }
-
-    _GLIBCXX20_CONSTEXPR
+    _GLIBCXX20_CONSTEXPR _GLIBCXX_ALWAYS_INLINE
     void
     _M_assume_normalized() const
     {
-      __GLIBCXX_BUILTIN_ASSUME (_M_normalized_p ());
+      __attribute__ ((__assume__ (_M_offset < unsigned(_S_word_bit))));
     }
 
     _GLIBCXX20_CONSTEXPR