[Bug tree-optimization/27799] adding unused char field inhibits optimization

[rguenther at suse dot de]

------- Comment #8 from rguenther at suse dot de  2008-03-04 21:35 -------
Subject: Re:  adding unused char field inhibits
 optimization

On Tue, 4 Mar 2008, dann at godzilla dot ics dot uci dot edu wrote:

> ------- Comment #7 from dann at godzilla dot ics dot uci dot edu  2008-03-04 21:32 -------
> (In reply to comment #6)
> > Actually RTL alias is just using the same routines.
> Might be, but the RTL level code that optimizes away the abort() in both
> testcases (if I remember well nonoverlapping_component_refs_p). 

I still have the abort () with -O2.

> > 
> >   # SMT.4_6 = VDEF <SMT.4_4(D)>
> >   # SMT.5_7 = VDEF <SMT.5_5(D)>
> >   x_1(D)->x = 0;
> >   # SMT.5_8 = VDEF <SMT.5_7>
> >   y_2(D)->y = 1;
> > 
> > vs.
> > 
> >   # SMT.18_5 = VDEF <SMT.18_4(D)>
> >   x_1(D)->x = 0;
> >   # SMT.19_7 = VDEF <SMT.19_6(D)>
> >   y_2(D)->y = 1;
> 
> That is for this testcase, but what about the impact on .final_cleanup for
> something big like combine.c? 

No idea, but feel free to check.

Richard.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27799