[llvm-commits] [PATCH] Improve codegen for non-constant BUILD_VECTORs on ARM

[James Molloy]

Hi Jim,

Thanks! Comments acted upon and committed in r163301.

Cheers,

James

On Thu, 2012-09-06 at 01:32 +0100, Jim Grosbach wrote:
> Some lines exceed 80 columns and/or have trailing whitespace.
>
> +  std::map<SDValue, int> ValueCounts;
>
> This seems a pretty good use-case for a DenseMap.
>
> Other than that, this looks great and is good to go. Thanks!
>
> -Jim
>
>
> On Sep 3, 2012, at 1:29 AM, James Molloy <James.Molloy at arm.com> wrote:
>
> > Hi,
> >
> > Currently if a BUILD_VECTOR is all constants but isn't a constant splat,
> > a chain of insertelements is created from undef.
> >
> > However in some cases it may be profitable to start from a different
> > base; consider "<5, 5, 6, 5>". This would be more profitable to start
> > from a base of a constant splat of "5", then mutate the third lane to
> > "6".
> >
> > The attached patch implements this, by searching for a "dominant"
> > constant value in the vector. A dominant value is defined as a value
> > that is present in more than half the lanes.
> >
> > Please review.
> >
> > Cheers,
> >
> > James<nonconstant_splats.diff>_______________________________________________
> > llvm-commits mailing list
> > llvm-commits at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>
>
>


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