float xfermodes (burn, dodge, softlight) in Sk8f, possibly using AVX.

src/core/SkOpts.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkOnce.h"
 #include "SkOpts.h"
 
@@ skipping 66 matching lines @@
     decltype(blit_row_color32) blit_row_color32 = sk_default::blit_row_color32;
 
     decltype(matrix_translate)       matrix_translate       = sk_default::matrix_translate;
     decltype(matrix_scale_translate) matrix_scale_translate = sk_default::matrix_scale_translate;
     decltype(matrix_affine)          matrix_affine          = sk_default::matrix_affine;
 
     // Each Init_foo() is defined in src/opts/SkOpts_foo.cpp.
     void Init_ssse3();
     void Init_sse41();
     void Init_sse42() { SkDEBUGCODE( SkDebugf("sse 4.2 detected\n"); ) }
-    void Init_avx()  { SkDEBUGCODE( SkDebugf("avx detected\n"); ) }
+    void Init_avx();
     void Init_avx2() { SkDEBUGCODE( SkDebugf("avx2 detected\n"); ) }
     void Init_neon();
     //TODO: _dsp2, _armv7, _armv8, _x86, _x86_64, _sse42, ... ?
 
     static void init() {
         // TODO: Chrome's not linking _sse* opts on iOS simulator builds.  Bug or feature?
     #if defined(SK_CPU_X86) && !defined(SK_BUILD_FOR_IOS)
         uint32_t abcd[] = {0,0,0,0};
         cpuid(abcd);
         if (abcd[2] & (1<< 9)) { Init_ssse3(); }
@@ skipping 21 matching lines @@
 
     SK_DECLARE_STATIC_ONCE(gInitOnce);
     void Init() { SkOnce(&gInitOnce, init); }
 
 #if SK_ALLOW_STATIC_GLOBAL_INITIALIZERS
     static struct AutoInit {
         AutoInit() { Init(); }
     } gAutoInit;
 #endif
 }