Unify some SkNx code

 - one base case and one N=1 case instead of two each (or three with doubles)
 - use SkNx_cast instead of FromBytes/toBytes
 - 4-at-a-time Sk4f::ToBytes becomes a special standalone Sk4f_ToBytes

If I did everything right, this'll be perf- and pixel- neutral.

https://gold.skia.org/search2?issue=1526523003&unt=true&query=source_type%3Dgm&master=false

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/1526523003

1 files changed, 61 insertions, 30 deletions

diff --git a/src/opts/SkNx_sse.h b/src/opts/SkNx_sse.h
index 9092f44480..f3952a9768 100644
--- a/src/opts/SkNx_sse.h
+++ b/src/opts/SkNx_sse.h
@@ -111,37 +111,9 @@ public:
     SkNx(float val)           : fVec( _mm_set1_ps(val) ) {}
     static SkNx Load(const float vals[4]) { return _mm_loadu_ps(vals); }
 
-    static SkNx FromBytes(const uint8_t bytes[4]) {
-        __m128i fix8 = _mm_cvtsi32_si128(*(const int*)bytes);
-    #if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSSE3
-        const char _ = ~0;  // Zero these bytes.
-        __m128i fix8_32 = _mm_shuffle_epi8(fix8, _mm_setr_epi8(0,_,_,_, 1,_,_,_, 2,_,_,_, 3,_,_,_));
-    #else
-        __m128i fix8_16 = _mm_unpacklo_epi8 (fix8,    _mm_setzero_si128()),
-                fix8_32 = _mm_unpacklo_epi16(fix8_16, _mm_setzero_si128());
-    #endif
-        return SkNx(_mm_cvtepi32_ps(fix8_32));
-        // TODO: use _mm_cvtepu8_epi32 w/SSE4.1?
-    }
-
     SkNx(float a, float b, float c, float d) : fVec(_mm_setr_ps(a,b,c,d)) {}
 
     void store(float vals[4]) const { _mm_storeu_ps(vals, fVec); }
-    void toBytes(uint8_t bytes[4]) const {
-        __m128i fix8_32 = _mm_cvttps_epi32(fVec),
-                fix8_16 = _mm_packus_epi16(fix8_32, fix8_32),
-                fix8    = _mm_packus_epi16(fix8_16, fix8_16);
-        *(int*)bytes = _mm_cvtsi128_si32(fix8);
-    }
-
-    static void ToBytes(uint8_t bytes[16],
-                        const SkNx& a, const SkNx& b, const SkNx& c, const SkNx& d) {
-        _mm_storeu_si128((__m128i*)bytes,
-                         _mm_packus_epi16(_mm_packus_epi16(_mm_cvttps_epi32(a.fVec),
-                                                           _mm_cvttps_epi32(b.fVec)),
-                                          _mm_packus_epi16(_mm_cvttps_epi32(c.fVec),
-                                                           _mm_cvttps_epi32(d.fVec))));
-    }
 
     SkNx operator + (const SkNx& o) const { return _mm_add_ps(fVec, o.fVec); }
     SkNx operator - (const SkNx& o) const { return _mm_sub_ps(fVec, o.fVec); }
@@ -253,6 +225,34 @@ public:
 };
 
 template <>
+class SkNx<4, uint8_t> {
+public:
+    SkNx(const __m128i& vec) : fVec(vec) {}
+
+    SkNx() {}
+    static SkNx Load(const uint8_t vals[4]) { return _mm_cvtsi32_si128(*(const int*)vals); }
+    void store(uint8_t vals[4]) const { *(int*)vals = _mm_cvtsi128_si32(fVec); }
+
+    // TODO as needed
+
+    __m128i fVec;
+};
+
+template <>
+class SkNx<8, uint8_t> {
+public:
+    SkNx(const __m128i& vec) : fVec(vec) {}
+
+    SkNx() {}
+    static SkNx Load(const uint8_t vals[8]) { return _mm_loadl_epi64((const __m128i*)vals); }
+    void store(uint8_t vals[8]) const { _mm_storel_epi64((__m128i*)vals, fVec); }
+
+    // TODO as needed
+
+    __m128i fVec;
+};
+
+template <>
 class SkNx<16, uint8_t> {
 public:
     SkNx(const __m128i& vec) : fVec(vec) {}
@@ -296,11 +296,42 @@ public:
 };
 
 
-template<>
-inline SkNx<4, int> SkNx_cast<int, float, 4>(const SkNx<4, float>& src) {
+template<> inline Sk4i SkNx_cast<int, float, 4>(const Sk4f& src) {
     return _mm_cvttps_epi32(src.fVec);
 }
 
+template<> inline Sk4b SkNx_cast<uint8_t, float, 4>(const Sk4f& src) {
+    auto _32 = _mm_cvttps_epi32(src.fVec);
+#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSSE3
+    const int _ = ~0;
+    return _mm_shuffle_epi8(_32, _mm_setr_epi8(0,4,8,12, _,_,_,_, _,_,_,_, _,_,_,_));
+#else
+    auto _16 = _mm_packus_epi16(_32, _32);
+    return     _mm_packus_epi16(_16, _16);
+#endif
+}
+
+template<> inline Sk4f SkNx_cast<float, uint8_t, 4>(const Sk4b& src) {
+#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSSE3
+    const int _ = ~0;
+    auto _32 = _mm_shuffle_epi8(src.fVec, _mm_setr_epi8(0,_,_,_, 1,_,_,_, 2,_,_,_, 3,_,_,_));
+#else
+    auto _16 = _mm_unpacklo_epi8(src.fVec, _mm_setzero_si128()),
+         _32 = _mm_unpacklo_epi16(_16,     _mm_setzero_si128());
+#endif
+    return _mm_cvtepi32_ps(_32);
+}
+
+static inline void Sk4f_ToBytes(uint8_t bytes[16],
+                                const Sk4f& a, const Sk4f& b, const Sk4f& c, const Sk4f& d) {
+    _mm_storeu_si128((__m128i*)bytes,
+                     _mm_packus_epi16(_mm_packus_epi16(_mm_cvttps_epi32(a.fVec),
+                                                       _mm_cvttps_epi32(b.fVec)),
+                                      _mm_packus_epi16(_mm_cvttps_epi32(c.fVec),
+                                                       _mm_cvttps_epi32(d.fVec))));
+}
+
+
 }  // namespace
 
 #endif//SkNx_sse_DEFINED