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Re: Use of vector instructions in memmov/memset expanding
On Wed, Sep 28, 2011 at 06:27:11PM +0200, Andi Kleen wrote:
> > There is no separate cost-table for Nehalem or SandyBridge - however,
> > I tuned generic32 and generic64 tables, that should improve
> > performance on modern processors. In old version REP-MOV was used - it
>
> The recommended heuristics have changed in Nehalem and Sandy-Bridge
> over earlier Intel CPUs.
Sorry what I meant is that it would be bad if -mtune=corei7(-avx)? was
slower than generic.
Adding new tables shouldn't be very difficult, even if they are the same
as generic.
-Andi