Introduce faster swapping primitives.

src/codegen.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 108 matching lines @@
   F(IsObject, 1, 1)                                                          \
   F(IsFunction, 1, 1)                                                        \
   F(IsUndetectableObject, 1, 1)                                              \
   F(StringAdd, 2, 1)                                                         \
   F(SubString, 3, 1)                                                         \
   F(StringCompare, 2, 1)                                                     \
   F(RegExpExec, 4, 1)                                                        \
   F(RegExpConstructResult, 3, 1)                                             \
   F(GetFromCache, 2, 1)                                                      \
   F(NumberToString, 1, 1)                                                    \
+  F(SwapElements, 3, 1)                                                      \
   F(MathPow, 2, 1)                                                           \
   F(MathSin, 1, 1)                                                           \
   F(MathCos, 1, 1)                                                           \
   F(MathSqrt, 1, 1)
 
 
 // Support for "structured" code comments.
 #ifdef DEBUG
 
 class Comment BASE_EMBEDDED {
@@ skipping 472 matching lines @@
  private:
   Major MajorKey() { return ToBoolean; }
   int MinorKey() { return 0; }
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CODEGEN_H_