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Re: Does unrolling prevents doloop optimizations?
- From: Ayal Zaks <ZAKS at il dot ibm dot com>
- To: Zdenek Dvorak <rakdver at kam dot mff dot cuni dot cz>
- Cc: gcc at gcc dot gnu dot org, Mircea Namolaru <namolaru at il dot ibm dot com>, Vladimir Yanovsky <volodyan at gmail dot com>
- Date: Sat, 30 Jun 2007 23:41:56 +0300
- Subject: Re: Does unrolling prevents doloop optimizations?
Zdenek Dvorak <rakdver@kam.mff.cuni.cz> wrote on 30/06/2007 20:36:12:
> Hello,
>
> > > > It doesn't seem that the number of iterations analysis from
loop-iv.c
> > deals
> > > > with EQ closing branches.
> > >
> > > loop-iv works just fine for EQ closing branches.
> > >
> >
> > Thanks for the clarification (I didn't see EQ in
iv_number_of_iterations's
> > switch (cond)).
>
> that is because we canonicalize the condition before that to a NE
> condition.
>
Ah, I see now that check_simple_exit does this reversal right before
calling iv_number_of_iterations. This is the desired
>any suitable branch reversal facility available?
so sms should definitely try to use get_simple_loop_desc instead of
doloop_condition_get.
Thanks, Ayal.