[PATCH 1/2] Cost model: Add check for reverse shuffles to CostModel analysis
Arnold Schwaighofer
aschwaighofer at apple.com
Sat Feb 9 11:52:43 PST 2013
They are related. This one is about modeling the cost of reverse shuffles correctly.
I will update the cost of v8i16 and v16i8 when I commit this patch. It all depends which patch goes in first :).
The code for checking is similar but not the same because they are at different stages of lowering.
On Feb 9, 2013, at 1:37 PM, Renato Golin <renato.golin at linaro.org> wrote:
> I'm guessing this could be used in your other patch about detecting reverse stride, are they related or conflicting?
>
> --renato
>
>
> On 8 February 2013 18:40, Arnold Schwaighofer <aschwaighofer at apple.com> wrote:
> Updated patch.
>
>
>
>
> Thanks
>
> On Feb 8, 2013, at 11:44 AM, Nadav Rotem <nrotem at apple.com> wrote:
>
> > LGTM! A few minor comments:
> >
> > There is an extra line break here.
> >
> > +
> > +static bool isReverseVectorMask(SmallVector<int, 16> &Mask) {
> > + for (unsigned i = 0, MaskSize = Mask.size(); i < MaskSize; ++i)
> > + if (Mask[i] != (int)(MaskSize - 1 - i))
> > + return false;
> > + return true;
> > +}
> > +
> >
> > We should also check for -1's in the mask.
> >
> > + if (NumVecElems == Mask.size() &&
> > + isReverseVectorMask(Mask))
> >
> >
> > The expression above can fit in one line.
> >
> >
> > Thanks,
> > Nadav
>
>
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