Narrow disabled vectorization further to just ConvolveHorizontally.

src/core/SkConvolver.cpp

Index: src/core/SkConvolver.cpp
diff --git a/src/core/SkConvolver.cpp b/src/core/SkConvolver.cpp
index 08d9f454968c4763bcb571236e4729835282f277..0ef683c5f73f871cf6cae823108a6ef0296d28f4 100644
--- a/src/core/SkConvolver.cpp
+++ b/src/core/SkConvolver.cpp
@@ -158,6 +158,31 @@ template<bool hasAlpha>
         }
     }
 
+    // There's a bug somewhere here with GCC autovectorization (-ftree-vectorize) on 32 bit builds.
+    // Dropping to -O2 disables -ftree-vectorize.  http://skbug.com/2575
+    #if defined(__i386) && SK_HAS_ATTRIBUTE(optimize) && defined(SK_RELEASE)
+        #define SK_MAYBE_DISABLE_VECTORIZATION __attribute__((optimize("O2")))
+    #else
+        #define SK_MAYBE_DISABLE_VECTORIZATION
+    #endif
+
+    SK_MAYBE_DISABLE_VECTORIZATION
+    static void ConvolveHorizontallyAlpha(const unsigned char* srcData,
+                                          const SkConvolutionFilter1D& filter,
+                                          unsigned char* outRow) {
+        return ConvolveHorizontally<true>(srcData, filter, outRow);
+    }
+
+    SK_MAYBE_DISABLE_VECTORIZATION
+    static void ConvolveHorizontallyNoAlpha(const unsigned char* srcData,
+                                            const SkConvolutionFilter1D& filter,
+                                            unsigned char* outRow) {
+        return ConvolveHorizontally<false>(srcData, filter, outRow);
+    }
+
+    #undef SK_MAYBE_DISABLE_VECTORIZATION
+
+
 // Does vertical convolution to produce one output row. The filter values and
 // length are given in the first two parameters. These are applied to each
 // of the rows pointed to in the |sourceDataRows| array, with each row
@@ -330,11 +355,6 @@ const SkConvolutionFilter1D::ConvolutionFixed* SkConvolutionFilter1D::GetSingleF
     return &fFilterValues[filter.fDataLocation];
 }
 
-// There's a bug somewhere in here with GCC autovectorization (-ftree-vectorize) on 32 bit builds.
-// Dropping to -O2 disables -ftree-vectorize.  http://skbug.com/2575
-#if defined(__i386) && SK_HAS_ATTRIBUTE(optimize) && defined(SK_RELEASE)
-    __attribute__((optimize("O2")))
-#endif
 void BGRAConvolve2D(const unsigned char* sourceData,
                     int sourceByteRowStride,
                     bool sourceHasAlpha,
@@ -425,11 +445,11 @@ void BGRAConvolve2D(const unsigned char* sourceData,
                         filterX, rowBuffer.advanceRow(), sourceHasAlpha);
                 } else {
                     if (sourceHasAlpha) {
-                        ConvolveHorizontally<true>(
+                        ConvolveHorizontallyAlpha(
                             &sourceData[(uint64_t)nextXRow * sourceByteRowStride],
                             filterX, rowBuffer.advanceRow());
                     } else {
-                        ConvolveHorizontally<false>(
+                        ConvolveHorizontallyNoAlpha(
                             &sourceData[(uint64_t)nextXRow * sourceByteRowStride],
                             filterX, rowBuffer.advanceRow());
                     }