------- Comment #7 from pinskia at gcc dot gnu dot org 2009-01-15 23:30 -------
PR 38747 has the best patch which allows most optimizations still but only
disabling it for the invalid cases when the aliasing sets are not equal.
Take:
struct S { unsigned f; };
int __attribute__((noinline))
foo ( struct S *p)
{
int *q = (int *)&p->f;
int i = *q;
return i + p->f;
}
We should be able to optimize this to just "tmp = p->f; return (int)(tmp +
tmp);" which we do with my patch unlike the one in comment #2 which disables
too many optimizations.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38748
