On Fri, 4 Mar 2016, Jeff Law wrote:
> On 03/03/2016 05:35 AM, Richard Biener wrote:
> >
> > The following patch adjusts strict_aliasing_warning to use
> > proper alias_set_subset_of instead of relying on alias_sets_conflict_p
> > as after the PR66110 fix aggregates with a char[] member do not
> > automatically behave like having alias-set zero. As a side-effect
> > the test will be somewhat stricter as well accessing a 'long' with
> > a struct { int i; long l; } * will now warn while it previously
> > didn't:
> >
> > struct S { int i; long l; };
> > long x;
> > struct S foo () { return *(struct S *)&x; }
> >
> > now warns:
> >
> > t.c: In function ‘foo’:
> > t.c:3:35: warning: dereferencing type-punned pointer will break
> > strict-aliasing rules [-Wstrict-aliasing]
> > struct S foo () { return *(struct S *)&x; }
> > ^
> > Bootstrap and regtest running on x86_64-unknown-linux-gnu, ok for trunk?
> >
> > Thanks,
> > Richard.
> >
> > 2016-03-03 Richard Biener <rguent...@suse.de>
> >
> > PR c++/70054
> > * c-common.c (strict_aliasing_warning): Use alias_set_subset_of
> > instead of alias_sets_conflict_p.
> >
> > * g++.dg/warn/Wstrict-aliasing-bogus-union-2.C: New testcase.
> > * gcc.dg/Wstrict-aliasing-struct-member.c: New testcase.
> The PR doesn't have a regression marker, but from reading the PR it's clearly
> a regression.
Yes, it is - sorry for not updating the bugzilla appropriately.
> OK for the trunk,
Thanks,
Richard.
