http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56165
--- Comment #15 from Alexander Kobets <akobets at mail dot ru> 2013-02-03 21:56:41 UTC --- (In reply to comment #14) > Not fake, but the default and smallest value, i.e. for x86_64 ABI we don't > allow lowering the value to smaller than ABI required alignments. Only for > 32-bit i?86 code it is allowed to lower it from 16 down to 4 bytes (the > argument to -mpreferred-stack-boundary is N where (1 << N) is the alignment). But no error is printed when I use -mpreferred-stack-boundary=4 on 64-bit CPU. Only when defined 0, then printed: error: -mpreferred-stack-boundary=0 is not between 4 and 12 while 4 is realy not worked.
