ARM: Add optimization for constant RHS in DoMulI (try 2)

src/utils.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 34 matching lines @@
 
 // Returns true iff x is a power of 2 (or zero). Cannot be used with the
 // maximally negative value of the type T (the -1 overflows).
 template <typename T>
 static inline bool IsPowerOf2(T x) {
   return IS_POWER_OF_TWO(x);
 }
 
 
 // X must be a power of 2.  Returns the number of trailing zeros.
-template <typename T>
-static inline int WhichPowerOf2(T x) {
+static inline int WhichPowerOf2(uint32_t x) {
   ASSERT(IsPowerOf2(x));
   ASSERT(x != 0);
-  if (x < 0) return 31;
   int bits = 0;
 #ifdef DEBUG
   int original_x = x;
 #endif
   if (x >= 0x10000) {
     bits += 16;
     x >>= 16;
   }
   if (x >= 0x100) {
     bits += 8;
@@ skipping 717 matching lines @@
 INLINE(Dest BitCast(const Source& source));
 
 template <class Dest, class Source>
 inline Dest BitCast(const Source& source) {
   return BitCastHelper<Dest, Source>::cast(source);
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_UTILS_H_