[Bug target/56564] movdqa on possibly-8-byte-aligned struct with -O3

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56564

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-03-08 12:38:20 UTC ---
Smaller testcase (-O2 -fpic):

struct S { long a, b; } s;
int foo (void)
{
  return ((long) &s) & 15;
}

is since http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=162943 optimized into
return 0, even when (probably) the psABI doesn't guarantee that.  But e.g. for
__builtin_memset (&s, 0, sizeof (s)); one can see already in 4.0 RTL dumps with
-O2 -fpic that MEM_ALIGN of s is assumed to be 128-bit.