Add SSSE3 acceleration for S32_D16_filter_DXDY

src/opts/opts_check_x86.cpp

Index: src/opts/opts_check_x86.cpp
diff --git a/src/opts/opts_check_x86.cpp b/src/opts/opts_check_x86.cpp
index 8fec2ba69c528040cbb02c2bd603bd1e00120a6f..f49ce3898342ee633fc1da3cf90e526823f60187 100644
--- a/src/opts/opts_check_x86.cpp
+++ b/src/opts/opts_check_x86.cpp
@@ -176,6 +176,8 @@ void SkBitmapProcState::platformProcs() {
     /* Check fSampleProc16 */
     if (fSampleProc16 == S32_D16_filter_DX) {
         fSampleProc16 = S32_D16_filter_DX_SSE2;
+    } else if (fSampleProc16 == S32_D16_filter_DXDY) {
+        fSampleProc16 = S32_D16_filter_DXDY_SSSE3;

[mtklein, 2014/12/02 15:19:05]

We need to check supports_simd(SK_CPU_SSE_LEVEL_SSSE3).

Why don't we pull that out into a local constant so it's more obvious?

if (!supports_simd(SK_CPU_SSE_LEVEL_SSE2)) {
   return;
}
const bool ssse3 = supports_simd(SK_CPU_SSE_LEVEL_SSSE3);
...

} else if (ssse3 && fSampleProc16 == S32_D16_filter_DXDY) {
   fSampleProc16 = S32_D16_filter_DXDY_SSSE3;
}
...

[qiankun1, 2014/12/02 15:58:43]

Done.

     }
 
     /* Check fMatrixProc */