fix for llvm max255 macro

BUG=none
TEST=libyuv_unittest --gtest_filter=*Add*
Review URL: https://webrtc-codereview.appspot.com/1346005

git-svn-id: http://libyuv.googlecode.com/svn/trunk@671 16f28f9a-4ce2-e073-06de-1de4eb20be90

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 670
+Version: 671
 License File: LICENSE
 
 Description:

include/libyuv/version.h

@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 670
+#define LIBYUV_VERSION 671
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

source/row_common.cc

@@ -732,13 +732,9 @@ void ARGBMultiplyRow_C(const uint8* src_argb0, const uint8* src_argb1,
 #undef REPEAT8
 #undef SHADE
 
-#ifdef __llvm__
+// llvm x86 is poor at ternary operator, so use branchless min/max.
 #define min0(v) ((-(v) >> 31) & (v))
-#define max255(v) (((256 - (v)) >> 31) | (v))
-#else
-#define min0(v) (((v) < 0) ? 0 : v)
-#define max255(v) (((v) > 255) ? 255 : (v))
-#endif
+#define max255(v) (((255 - (v)) >> 31) | (v))
 #define SHADE(f, v) max255(v + f)
 
 void ARGBAddRow_C(const uint8* src_argb0, const uint8* src_argb1,