------- Comment #7 from mikulas at artax dot karlin dot mff dot cuni dot cz 2009-07-23 13:49 ------- See bug #27537, quoting "GNU/Linux follows the SYSV x86 ABI which is documented, maybe you cannot find it but it does exist. The SYSV x86 ABI says the stack is aligned 4 byte aligned."
That bug seems to reappear. As Agner noted, 16-byte stack alignment requirement also break compatibility with Intel CC. I found even some part of current glibc that violates this 16-byte alignment (calling push %eax; call exit from the assembler without aligning the stack size). Another point: if gcc realigns the stack, why then use movdqu to store the values on the stack? That is suboptimal. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40838
