Sk4x4f: Simplify x86 down to SSE2.
- This drops the minimum requirement for Sk4x4f on x86 to SSE2 by
removing calls to _mm_shuffle_epi8(). Instead we use good old
shifting and masking.
- Performance is very similar to SSSE3, close enough I'm having trouble
telling which is faster. I think we should let ourselves circle back
on whether we need an SSSE3 version later. When possible it's nice
to stick to SSE2: it's most available, and performs most uniformly
across different chips.
This makes Sk4x4f fast on Windows and Linux, and may help mobile x86.
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1817353005
Review URL: https://codereview.chromium.org/1817353005
1 file changed