------- Comment #6 from jakub at gcc dot gnu dot org 2008-11-03 16:17 -------
4.2 doesn't realign stack except for main, only gcc 4.4 does and only for
alignments larger than 16 bytes (and only on i386/x86_64).
You can use an optimization barrier to force a check, but I think it is a bad
idea to slow down a library just because users might call it with bad stack
alignment, using -mpreferred-stack-boundary is an ABI switch, people who mix
code with different ABIs get what they deserve.
Say
uintptr_t aladdr = (uintptr_t) altest;
asm ("" : "+r" (aladdr));
if ((aladdr & 15) != 0)
puts ("stack not properly aligned");
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38001
