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Re: k-byte memset/memcpy/strlen builtins


On Thu, Jan 12, 2017 at 9:26 AM, Robin Dapp <rdapp@linux.vnet.ibm.com> wrote:
>> Yes, for memset with larger element we could add an optab plus
>> internal function combination and use that when the target wants.  Or
>> always use such IFN and fall back to loopy expansion.
>
> So, adding additional patterns in tree-loop-distribute.c (and mapping
> them to dedicated optabs) is fine? Or does the yes refer to the
> "else"/"or" part of my question (how would the backend recognize the
> patterns then)?

Yes, enhancing tree-loop-distribution.c with extra patterns is fine (hey, there
were supposed to be patterns for all of lapack & friends ... ;))

The question is only whether loop-distribution should always create the IFN
or just if the backend has an optab so expansion is trivial (rather than
needing to re-build a loop doing the operation).

Richard.

>> I'd say a multibyte memchr might make sense, but strlen specifically?
>> Not sure.
>
> ok, memchr would also work for the snippet I have in mind.
>
> Regards
>  Robin
>


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