[Bug target/56165] Missed optimization for 'noreturn' functions

[akobets at mail dot ru]

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.