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Re: Loop peeling


On Tue, Oct 28, 2014 at 4:55 PM, Evandro Menezes <e.menezes@samsung.com> wrote:
> While doing some benchmark flag mining on AArch64, I noticed that
> -fpeel-loops was a mined option often.  As a matter of fact, when using it
> always, even without FDO, it seemed to raise most benchmarks and to leave
> almost all of the rest flat, with a barely noticeable cost in code-size.  It
> seems to me that it might be safe enough to be implied perhaps at -O3.  Is
> there any reason why this never came into being?

Not sure, but peeling is/was very stupid (peeling 8 times unconditionally
or not at all).  At least without FDO (and with -fprofile-use it is enabled).
Similar case for -funroll-loops.

For GCC 5 peeling now moved to GIMPLE, so maybe things changed
for that (but I'd doubt that).  Honza?

Thanks,
Richard.

> Thank you,
>
> --
> Evandro Menezes                              Austin, TX
>
>
>


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