tree 79583ba4df443f9d49ce4d0870b5b461c8b6d5b1
parent 4c11b3f8a2d9919a21110dbdd29e67e5cbaa41fb
author mtklein <mtklein@chromium.org> 1448056399 -0800
committer Commit bot <commit-bot@chromium.org> 1448056399 -0800

Add SkNx_cast().

SkNx_cast() can cast between any of our vector types,
provided they have the same number of elements.

Any types should work with the default implementation,
and we can drop in specializations as needed, like the
SSE and NEON Sk4f -> Sk4i I included here as an example.

To make this work, I made some internal name changes:
    SkNi<N,T> -> SkNx<N, T>
    SkNf<N>   -> SkNx<N, float>
User aliases (Sk4f, Sk16b, etc.) stay the same.
We can land this first (it's PS1) if that makes things easier.

BUG=skia:
CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot

Review URL: https://codereview.chromium.org/1464623002