Mike's radial gradient CL with better float -> int.

src/opts/SkNx_sse.h

Index: src/opts/SkNx_sse.h
diff --git a/src/opts/SkNx_sse.h b/src/opts/SkNx_sse.h
index 46ddcb2d12559118805ca747fdc6d7187b389756..2608525bd0189530b16ca470de56683831358803 100644
--- a/src/opts/SkNx_sse.h
+++ b/src/opts/SkNx_sse.h
@@ -142,6 +142,44 @@ private:
 };
 
 template <>
+class SkNi<4, int> {
+public:
+    SkNi(const __m128i& vec) : fVec(vec) {}
+
+    SkNi() {}
+    explicit SkNi(int val) : fVec(_mm_set1_epi32(val)) {}
+    static SkNi Load(const int vals[4]) { return _mm_loadu_si128((const __m128i*)vals); }
+    SkNi(int a, int b, int c, int d) : fVec(_mm_setr_epi32(a,b,c,d)) {}
+
+    void store(int vals[4]) const { _mm_storeu_si128((__m128i*)vals, fVec); }
+
+    SkNi operator + (const SkNi& o) const { return _mm_add_epi32(fVec, o.fVec); }
+    SkNi operator - (const SkNi& o) const { return _mm_sub_epi32(fVec, o.fVec); }
+    SkNi operator * (const SkNi& o) const {
+        __m128i mul20 = _mm_mul_epu32(fVec, o.fVec),
+                mul31 = _mm_mul_epu32(_mm_srli_si128(fVec, 4), _mm_srli_si128(o.fVec, 4));
+        return _mm_unpacklo_epi32(_mm_shuffle_epi32(mul20, _MM_SHUFFLE(0,0,2,0)),
+                                  _mm_shuffle_epi32(mul31, _MM_SHUFFLE(0,0,2,0)));
+    }
+
+    SkNi operator << (int bits) const { return _mm_slli_epi32(fVec, bits); }
+    SkNi operator >> (int bits) const { return _mm_srai_epi32(fVec, bits); }
+
+    template <int k> int kth() const {
+        SkASSERT(0 <= k && k < 4);
+        switch (k) {
+            case 0: return _mm_cvtsi128_si32(fVec);
+            case 1: return _mm_cvtsi128_si32(_mm_srli_si128(fVec,  4));
+            case 2: return _mm_cvtsi128_si32(_mm_srli_si128(fVec,  8));
+            case 3: return _mm_cvtsi128_si32(_mm_srli_si128(fVec, 12));
+            default: SkASSERT(false); return 0;
+        }
+    }
+protected:
+    __m128i fVec;
+};
+
+template <>
 class SkNf<4, float> {
     typedef SkNb<4, 4> Nb;
 public:
@@ -154,6 +192,8 @@ public:
 
     void store(float vals[4]) const { _mm_storeu_ps(vals, fVec); }
 
+    SkNi<4, int> castTrunc() const { return _mm_cvttps_epi32(fVec); }
+
     SkNf operator + (const SkNf& o) const { return _mm_add_ps(fVec, o.fVec); }
     SkNf operator - (const SkNf& o) const { return _mm_sub_ps(fVec, o.fVec); }
     SkNf operator * (const SkNf& o) const { return _mm_mul_ps(fVec, o.fVec); }