Add noinline for GCC 4.6, which seems to vectorize after inlining.

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 141 matching lines @@
             outRow[outX * 4 + 0] = ClampTo8(accum[0]);
             outRow[outX * 4 + 1] = ClampTo8(accum[1]);
             outRow[outX * 4 + 2] = ClampTo8(accum[2]);
             if (hasAlpha) {
                 outRow[outX * 4 + 3] = ClampTo8(accum[3]);
             }
         }
     }
 
     // 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
+    // Dropping to -O2 disables -ftree-vectorize.  GCC 4.6 needs noinline.  http://skbug.com/2575
     #if defined(__i386) && SK_HAS_ATTRIBUTE(optimize) && defined(SK_RELEASE)
-        #define SK_MAYBE_DISABLE_VECTORIZATION __attribute__((optimize("O2")))
+        #define SK_MAYBE_DISABLE_VECTORIZATION __attribute__((optimize("O2"), noinline))
     #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);
     }
@@ skipping 302 matching lines @@
                                                filterX.numValues(), curOutputRow,
                                                sourceHasAlpha);
         } else {
             ConvolveVertically(filterValues, filterLength,
                                firstRowForFilter,
                                filterX.numValues(), curOutputRow,
                                sourceHasAlpha);
         }
     }
 }