Merge pull request #133 from JunHe77:simd

PiperOrigin-RevId: 393681630

snappy-internal.h

@@ -33,13 +33,30 @@
 
 #include "snappy-stubs-internal.h"
 
+#if SNAPPY_HAVE_SSSE3
+// Please do not replace with <x86intrin.h> or with headers that assume more
+// advanced SSE versions without checking with all the OWNERS.
+#include <emmintrin.h>
+#include <tmmintrin.h>
+#endif
+
+#if SNAPPY_HAVE_NEON
+#include <arm_neon.h>
+#endif
+
+#if SNAPPY_HAVE_SSSE3 || SNAPPY_HAVE_NEON
+#define SNAPPY_HAVE_VECTOR_BYTE_SHUFFLE 1
+#else
+#define SNAPPY_HAVE_VECTOR_BYTE_SHUFFLE 0
+#endif
+
 namespace snappy {
 namespace internal {
 
 #if SNAPPY_HAVE_VECTOR_BYTE_SHUFFLE
 #if SNAPPY_HAVE_SSSE3
 using V128 = __m128i;
-#else
+#elif SNAPPY_HAVE_NEON
 using V128 = uint8x16_t;
 #endif
 
@@ -72,7 +89,7 @@ inline V128 V128_Shuffle(V128 input, V128 shuffle_mask) {
 
 inline V128 V128_DupChar(char c) { return _mm_set1_epi8(c); }
 
-#else
+#elif SNAPPY_HAVE_NEON
 inline V128 V128_Load(const V128* src) {
   return vld1q_u8(reinterpret_cast<const uint8_t*>(src));
 }