[PATCH,rs6000] Fine-tune vec_construct direct move cost

Segher Boessenkool segher@kernel.crashing.org
Fri Jul 21 22:25:00 GMT 2017


Hi Bill,

On Fri, Jul 21, 2017 at 10:40:43AM -0500, Bill Schmidt wrote:
> In https://gcc.gnu.org/ml/gcc-patches/2017-05/msg00924.html, I raised the
> vectorization cost for a vec_construct operation that requires direct
> moves between GPRs and VSRs.  The cost equation I substituted has since
> proven to be slightly more conservative than attended, and we're seeing
> some cases of SLP vectorization being avoided that should not be.  This
> patch adjusts the equation to reduce the cost somewhat.
> 
> I've tested this to ensure the cases previously seen are now being
> vectorized again, and done some benchmark testing that shows no measurable
> result, positive or negative.  So this is just minor fine-tuning, but
> still important to get right.
> 
> Bootstrapped and tested on powerpc64le-unknown-linux-gnu with no regressions.
> Is this ok for trunk?

Sure, thanks!


Segher



More information about the Gcc-patches mailing list