libwebp: cherry-pick arm gcc-4.9 fix

third_party/libwebp/dsp/lossless.c

 // Copyright 2012 Google Inc. All Rights Reserved.
 //
 // Use of this source code is governed by a BSD-style license
 // that can be found in the COPYING file in the root of the source
 // tree. An additional intellectual property rights grant can be found
 // in the file PATENTS. All contributing project authors may
 // be found in the AUTHORS file in the root of the source tree.
 // -----------------------------------------------------------------------------
 //
 // Image transforms and color space conversion methods for lossless decoder.
@@ skipping 432 matching lines @@
 static WEBP_INLINE uint32_t ClampedAddSubtractHalf(uint32_t c0, uint32_t c1,
                                                    uint32_t c2) {
   const uint32_t ave = Average2(c0, c1);
   const int a = AddSubtractComponentHalf(ave >> 24, c2 >> 24);
   const int r = AddSubtractComponentHalf((ave >> 16) & 0xff, (c2 >> 16) & 0xff);
   const int g = AddSubtractComponentHalf((ave >> 8) & 0xff, (c2 >> 8) & 0xff);
   const int b = AddSubtractComponentHalf((ave >> 0) & 0xff, (c2 >> 0) & 0xff);
   return ((uint32_t)a << 24) | (r << 16) | (g << 8) | b;
 }
 
-static WEBP_INLINE int Sub3(int a, int b, int c) {
+// gcc-4.9 on ARM generates incorrect code in Select() when Sub3() is inlined.
+#if defined(__arm__) && LOCAL_GCC_VERSION == 0x409
+# define LOCAL_INLINE __attribute__ ((noinline))
+#else
+# define LOCAL_INLINE WEBP_INLINE
+#endif
+
+static LOCAL_INLINE int Sub3(int a, int b, int c) {
   const int pb = b - c;
   const int pa = a - c;
   return abs(pb) - abs(pa);
 }
 
+#undef LOCAL_INLINE
+
 static WEBP_INLINE uint32_t Select(uint32_t a, uint32_t b, uint32_t c) {
   const int pa_minus_pb =
       Sub3((a >> 24)       , (b >> 24)       , (c >> 24)       ) +
       Sub3((a >> 16) & 0xff, (b >> 16) & 0xff, (c >> 16) & 0xff) +
       Sub3((a >>  8) & 0xff, (b >>  8) & 0xff, (c >>  8) & 0xff) +
       Sub3((a      ) & 0xff, (b      ) & 0xff, (c      ) & 0xff);
   return (pa_minus_pb <= 0) ? a : b;
 }
 
 //------------------------------------------------------------------------------
@@ skipping 1152 matching lines @@
 #endif
 #if defined(WEBP_USE_MIPS32)
     if (VP8GetCPUInfo(kMIPS32)) {
       VP8LDspInitMIPS32();
     }
 #endif
   }
 }
 
 //------------------------------------------------------------------------------