Focus disabled optimizations on just BGRAConvolve2D, and only 32-bit.

src/core/SkConvolver.cpp

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "SkConvolver.h"
 #include "SkSize.h"
 #include "SkTypes.h"
 
 namespace {
 
@@ skipping 312 matching lines @@
     *filterOffset = filter.fOffset;
     *filterLength = filter.fTrimmedLength;
     *specifiedFilterlength = filter.fLength;
     if (filter.fTrimmedLength == 0) {
         return NULL;
     }
 
     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)
+    __attribute__((optimize("O2")))
+#endif
 void BGRAConvolve2D(const unsigned char* sourceData,
                     int sourceByteRowStride,
                     bool sourceHasAlpha,
                     const SkConvolutionFilter1D& filterX,
                     const SkConvolutionFilter1D& filterY,
                     int outputByteRowStride,
                     unsigned char* output,
                     const SkConvolutionProcs& convolveProcs,
                     bool useSimdIfPossible) {
 
@@ skipping 109 matching lines @@
                                                filterX.numValues(), curOutputRow,
                                                sourceHasAlpha);
         } else {
             ConvolveVertically(filterValues, filterLength,
                                firstRowForFilter,
                                filterX.numValues(), curOutputRow,
                                sourceHasAlpha);
         }
     }
 }