Lower limit for complex memcpy on non-ia32 architectures.

R=jkummerow@chromium.org
BUG=chromium:196330

Review URL: https://codereview.chromium.org/12790012

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14025 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/platform.h

@@ -348,7 +348,7 @@ class OS {
   static void MemCopy(void* dest, const void* src, size_t size) {
     memcpy(dest, src, size);
   }
-  static const int kMinComplexMemCopy = 256;
+  static const int kMinComplexMemCopy = 16 * kPointerSize;
 #endif  // V8_TARGET_ARCH_IA32
 
   static int GetCurrentProcessId();