http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51500
--- Comment #12 from Uros Bizjak <ubizjak at gmail dot com> 2012-01-30 16:39:04 UTC --- (In reply to comment #11) > + *(unsigned int*) &__tramp[24] = 0x8304244c; /* xchgl 4(%esp),%ecx*/ \ Don't use this insn, it implies lock prefix and costs hundreds of cycles.