Port S32A_opaque blit row to SkOpts.

src/opts/SkBlitRow_opts.h

Index: src/opts/SkBlitRow_opts.h
diff --git a/src/opts/SkBlitRow_opts.h b/src/opts/SkBlitRow_opts.h
index f000f30fd09bd40448cb1a80af10c0b767da8c8c..94d9ee996eb258737e22d623e13063b134ac3d45 100644
--- a/src/opts/SkBlitRow_opts.h
+++ b/src/opts/SkBlitRow_opts.h
@@ -9,6 +9,12 @@
 #define SkBlitRow_opts_DEFINED
 
 #include "Sk4px.h"
+#include "SkColorPriv.h"
+#include "SkMSAN.h"
+
+#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
+    #include "SkColor_opts_SSE2.h"
+#endif
 
 namespace SK_OPTS_NS {
 
@@ -17,7 +23,8 @@ namespace SK_OPTS_NS {
 // and it's quite a bit faster than blend_perfect.
 //
 // blend_256_round_alt is our currently blessed algorithm.  Please use it or an analogous one.
-static void blit_row_color32(SkPMColor* dst, const SkPMColor* src, int count, SkPMColor color) {
+static inline
+void blit_row_color32(SkPMColor* dst, const SkPMColor* src, int count, SkPMColor color) {
     unsigned invA = 255 - SkGetPackedA32(color);
     invA += invA >> 7;
     SkASSERT(invA < 256);  // We've should have already handled alpha == 0 externally.
@@ -30,6 +37,167 @@ static void blit_row_color32(SkPMColor* dst, const SkPMColor* src, int count, Sk
     });
 }
 
+static inline
+void blit_row_s32a_opaque(SkPMColor* dst, const SkPMColor* src, int len, U8CPU alpha) {
+    SkASSERT(alpha == 0xFF);
+    sk_msan_assert_initialized(src, src+len);
+
+#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE41
+    while (len >= 16) {
+        // Load 16 source pixels.
+        auto s0 = _mm_loadu_si128((const __m128i*)(src) + 0),
+             s1 = _mm_loadu_si128((const __m128i*)(src) + 1),
+             s2 = _mm_loadu_si128((const __m128i*)(src) + 2),
+             s3 = _mm_loadu_si128((const __m128i*)(src) + 3);
+
+        const auto alphaMask = _mm_set1_epi32(0xFF000000);
+
+        auto ORed = _mm_or_si128(s3, _mm_or_si128(s2, _mm_or_si128(s1, s0)));
+        if (_mm_testz_si128(ORed, alphaMask)) {
+            // All 16 source pixels are transparent.  Nothing to do.
+            src += 16;
+            dst += 16;
+            len -= 16;
+            continue;
+        }
+
+        auto d0 = (__m128i*)(dst) + 0,
+             d1 = (__m128i*)(dst) + 1,
+             d2 = (__m128i*)(dst) + 2,
+             d3 = (__m128i*)(dst) + 3;
+
+        auto ANDed = _mm_and_si128(s3, _mm_and_si128(s2, _mm_and_si128(s1, s0)));
+        if (_mm_testc_si128(ANDed, alphaMask)) {
+            // All 16 source pixels are opaque.  SrcOver becomes Src.
+            _mm_storeu_si128(d0, s0);
+            _mm_storeu_si128(d1, s1);
+            _mm_storeu_si128(d2, s2);
+            _mm_storeu_si128(d3, s3);
+            src += 16;
+            dst += 16;
+            len -= 16;
+            continue;
+        }
+
+        // TODO: This math is wrong.
+        // Do SrcOver.
+        _mm_storeu_si128(d0, SkPMSrcOver_SSE2(s0, _mm_loadu_si128(d0)));
+        _mm_storeu_si128(d1, SkPMSrcOver_SSE2(s1, _mm_loadu_si128(d1)));
+        _mm_storeu_si128(d2, SkPMSrcOver_SSE2(s2, _mm_loadu_si128(d2)));
+        _mm_storeu_si128(d3, SkPMSrcOver_SSE2(s3, _mm_loadu_si128(d3)));
+        src += 16;
+        dst += 16;
+        len -= 16;
+    }
+
+#elif SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
+    while (len >= 16) {
+        // Load 16 source pixels.
+        auto s0 = _mm_loadu_si128((const __m128i*)(src) + 0),
+             s1 = _mm_loadu_si128((const __m128i*)(src) + 1),
+             s2 = _mm_loadu_si128((const __m128i*)(src) + 2),
+             s3 = _mm_loadu_si128((const __m128i*)(src) + 3);
+
+        const auto alphaMask = _mm_set1_epi32(0xFF000000);
+
+        auto ORed = _mm_or_si128(s3, _mm_or_si128(s2, _mm_or_si128(s1, s0)));
+        if (0xffff == _mm_movemask_epi8(_mm_cmpeq_epi8(_mm_and_si128(ORed, alphaMask),
+                                                       _mm_setzero_si128()))) {
+            // All 16 source pixels are transparent.  Nothing to do.
+            src += 16;
+            dst += 16;
+            len -= 16;
+            continue;
+        }
+
+        auto d0 = (__m128i*)(dst) + 0,
+             d1 = (__m128i*)(dst) + 1,
+             d2 = (__m128i*)(dst) + 2,
+             d3 = (__m128i*)(dst) + 3;
+
+        auto ANDed = _mm_and_si128(s3, _mm_and_si128(s2, _mm_and_si128(s1, s0)));
+        if (0xffff == _mm_movemask_epi8(_mm_cmpeq_epi8(_mm_and_si128(ANDed, alphaMask),
+                                                       alphaMask))) {
+            // All 16 source pixels are opaque.  SrcOver becomes Src.
+            _mm_storeu_si128(d0, s0);
+            _mm_storeu_si128(d1, s1);
+            _mm_storeu_si128(d2, s2);
+            _mm_storeu_si128(d3, s3);
+            src += 16;
+            dst += 16;
+            len -= 16;
+            continue;
+        }
+
+        // TODO: This math is wrong.
+        // Do SrcOver.
+        _mm_storeu_si128(d0, SkPMSrcOver_SSE2(s0, _mm_loadu_si128(d0)));
+        _mm_storeu_si128(d1, SkPMSrcOver_SSE2(s1, _mm_loadu_si128(d1)));
+        _mm_storeu_si128(d2, SkPMSrcOver_SSE2(s2, _mm_loadu_si128(d2)));
+        _mm_storeu_si128(d3, SkPMSrcOver_SSE2(s3, _mm_loadu_si128(d3)));
+
+        src += 16;
+        dst += 16;
+        len -= 16;
+    }
+
+#elif defined(SK_ARM_HAS_NEON)
+    while (len >= 4) {
+        if ((src[0] | src[1] | src[2] | src[3]) == 0x00000000) {
+            // All 16 source pixels are transparent.  Nothing to do.
+            src += 4;
+            dst += 4;
+            len -= 4;
+            continue;
+        }
+
+        if ((src[0] & src[1] & src[2] & src[3]) >= 0xFF000000) {
+            // All 16 source pixels are opaque.  SrcOver becomes Src.
+            dst[0] = src[0];
+            dst[1] = src[1];
+            dst[2] = src[2];
+            dst[3] = src[3];
+            src += 4;
+            dst += 4;
+            len -= 4;
+            continue;
+        }
+
+        // Load 4 source and destination pixels.
+        auto src0 = vreinterpret_u8_u32(vld1_u32(src+0)),
+             src2 = vreinterpret_u8_u32(vld1_u32(src+2)),
+             dst0 = vreinterpret_u8_u32(vld1_u32(dst+0)),
+             dst2 = vreinterpret_u8_u32(vld1_u32(dst+2));
+
+        // TODO: This math is wrong.
+        const uint8x8_t alphas = vcreate_u8(0x0707070703030303);
+        auto invSA0_w = vsubw_u8(vdupq_n_u16(256), vtbl1_u8(src0, alphas)),
+             invSA2_w = vsubw_u8(vdupq_n_u16(256), vtbl1_u8(src2, alphas));
+
+        auto dstInvSA0 = vmulq_u16(invSA0_w, vmovl_u8(dst0)),
+             dstInvSA2 = vmulq_u16(invSA2_w, vmovl_u8(dst2));
+
+        dst0 = vadd_u8(src0, vshrn_n_u16(dstInvSA0, 8));
+        dst2 = vadd_u8(src2, vshrn_n_u16(dstInvSA2, 8));
+
+        vst1_u32(dst+0, vreinterpret_u32_u8(dst0));
+        vst1_u32(dst+2, vreinterpret_u32_u8(dst2));
+
+        src += 4;
+        dst += 4;
+        len -= 4;
+    }
+#endif
+
+    while (len-- > 0) {
+        if (*src) {
+            *dst = (*src >= 0xFF000000) ? *src : SkPMSrcOver(*src, *dst);
+        }
+        src++;
+        dst++;
+    }
+}
+
 }  // SK_OPTS_NS
 
 #endif//SkBlitRow_opts_DEFINED