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Re: [patch] Enable -fweb and -frename-registers when unrolling


Hello,

> >         PR rtl-optimization/20376
> >         * toplev.c (process_options): Enable -fweb and -frename-registers when
> >         unrolling.
> 
> when unrolling or peeling?

just when unrolling.

> Or did you rather mean not to set these with
> only flag_peel_loops set?  I regularly use only -fpeel-loops to get small
> loops peeled completely; do you expect it as a win there, too?

The loops should be peeled completely at tree level; ssa form makes -fweb 
useless in this case.  I am not sure about -frename-registers.

What I perhaps forgot to mention is that -frename-registers helps also
without unrolling, but less than with it.  -fweb has no significant
effect without unrolling (probably because of ssa).

Zdenek


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