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

src/core/SkConvolver.cpp

Index: src/core/SkConvolver.cpp
diff --git a/src/core/SkConvolver.cpp b/src/core/SkConvolver.cpp
index 0ef683c5f73f871cf6cae823108a6ef0296d28f4..4633c2e2eab970de5372d07ce4ea5c1c1ecc587f 100644
--- a/src/core/SkConvolver.cpp
+++ b/src/core/SkConvolver.cpp
@@ -159,9 +159,9 @@ 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
+    // 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