http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42734
--- Comment #36 from Paolo Carlini <paolo.carlini at oracle dot com> 2010-10-15 23:41:54 UTC --- (In reply to comment #32) > Does the front-end disable the HAVE_SYNC_COMPARE_AND_SWAP macros if you > compile > with (implicit or explicit) march=i386 ? I'm jumping in just in case this point hasn't been clarified already: I added to the front end the __GCC_HAVE_SYNC_COMPARE_AND_SWAP_* macros, and indeed, are sensitive to the *actual* command-line options: with -march=i386 are definitely undefined.
