[Bug tree-optimization/35518] [4.4 Regression] FAIL: gcc.c-torture/execute/20040709-1.c execution at -O2 and above

["rguenther at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #25 from rguenther at suse dot de  2008-06-26 09:33 -------
Subject: Re:  [4.4 Regression] FAIL:
 gcc.c-torture/execute/20040709-1.c execution at -O2 and above

On Thu, 26 Jun 2008, aoliva at gcc dot gnu dot org wrote:

> ------- Comment #24 from aoliva at gcc dot gnu dot org  2008-06-26 00:33 -------
> It's not just the result type that changed.  You actually changed the type of
> the variable created to hold the group of bit fields, out of which we further
> extract members that were not mapped to separate variables.  This might affect
> bitfield simplifications based on mode size rather than type width.  I can't
> say that's it, but I know I may have based some code on this assumption that
> you broke.
>
> It also seems to me that this change to the base type of the variable breaks
> sra_build_elt_assignment(), because the by-design conditions might no longer be
> met.  Finally, I don't see how you could assume that the else block for the if
> full-width bit-field could be extracted with as little as a cast.
>
> This is what jumped at me at first.  I haven't actually built compilers based
> on the state before and after your patch to tell whether that's it, but these
> are the most likely culprits.
>
> I hope this helps,

No, sorry.  Please point me to the place where I changed the type of the
variable created to hold the group of bit fields.

Richard.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35518