Add swizzle for rgb8888.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1746153002
CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot

Review URL: https://codereview.chromium.org/1746153002

2 files changed, 18 insertions, 1 deletions

diff --git a/src/opts/SkNx_neon.h b/src/opts/SkNx_neon.h
index 1acd7a00f4..52b2e73798 100644
--- a/src/opts/SkNx_neon.h
+++ b/src/opts/SkNx_neon.h
@@ -305,12 +305,20 @@ public:
     SkNx(const uint8x8_t& vec) : fVec(vec) {}
 
     SkNx() {}
+    SkNx(uint8_t a, uint8_t b, uint8_t c, uint8_t d) {
+        fVec = (uint8x8_t){a,b,c,d, 0,0,0,0};
+    }
     static SkNx Load(const void* ptr) {
         return (uint8x8_t)vld1_dup_u32((const uint32_t*)ptr);
     }
     void store(void* ptr) const {
         return vst1_lane_u32((uint32_t*)ptr, (uint32x2_t)fVec, 0);
     }
+    uint8_t operator[](int k) const {
+        SkASSERT(0 <= k && k < 4);
+        union { uint8x8_t v; uint8_t us[8]; } pun = {fVec};
+        return pun.us[k&3];
+    }
 
     // TODO as needed
 
diff --git a/src/opts/SkNx_sse.h b/src/opts/SkNx_sse.h
index b6da080317..34b58c10ed 100644
--- a/src/opts/SkNx_sse.h
+++ b/src/opts/SkNx_sse.h
@@ -235,12 +235,21 @@ public:
 template <>
 class SkNx<4, uint8_t> {
 public:
+    SkNx() {}
     SkNx(const __m128i& vec) : fVec(vec) {}
+    SkNx(uint8_t a, uint8_t b, uint8_t c, uint8_t d)
+        : fVec(_mm_setr_epi8(a,b,c,d, 0,0,0,0, 0,0,0,0, 0,0,0,0)) {}
+
 
-    SkNx() {}
     static SkNx Load(const void* ptr) { return _mm_cvtsi32_si128(*(const int*)ptr); }
     void store(void* ptr) const { *(int*)ptr = _mm_cvtsi128_si32(fVec); }
 
+    uint8_t operator[](int k) const {
+        SkASSERT(0 <= k && k < 4);
+        union { __m128i v; uint8_t us[16]; } pun = {fVec};
+        return pun.us[k&3];
+    }
+
     // TODO as needed
 
     __m128i fVec;