On 1/20/06, Mark Mitchell <[EMAIL PROTECTED]> wrote: > Richard Guenther wrote: > > > A patch was also posted based on ideas in the audit trail. It's third > > incarnation at > > http://gcc.gnu.org/ml/gcc-patches/2006-01/msg00967.html > > would need a review. > > This patch uses "type_i == type_j" which is usually a mistake; are we > sure we don't need the usual type-equality predicate functions? > > Also, why doesn't: > > union U { char c; int i; }; > struct S { union U u; }; > struct T { union U u; }; > > present the same problem between S and T? S and T will fail the type_i > == type_j test, but does that keep us safe? In general, I think the
objects_must_conflict_p (type_i, type_j) doesn't say they must conflict now and so we put it in a separate partition. I.e. get_alias_set will return a different alias set for S and T. > patch needs a paragraph-long comment explaining what the problem is and > how this approach solves it. Ok, I'll try to come up with an explanation. Richard.
