[Isolates] Merge from bleeding_edge to isolates, revisions 6100-6300.

src/x64/regexp-macro-assembler-x64.cc

Index: src/x64/regexp-macro-assembler-x64.cc
===================================================================
--- src/x64/regexp-macro-assembler-x64.cc	(revision 6941)
+++ src/x64/regexp-macro-assembler-x64.cc	(working copy)
@@ -224,9 +224,7 @@
   // If input is ASCII, don't even bother calling here if the string to
   // match contains a non-ascii character.
   if (mode_ == ASCII) {
-    for (int i = 0; i < str.length(); i++) {
-      ASSERT(str[i] <= String::kMaxAsciiCharCodeU);
-    }
+    ASSERT(String::IsAscii(str.start(), str.length()));
   }
 #endif
   int byte_length = str.length() * char_size();
@@ -691,7 +689,7 @@
 
 void RegExpMacroAssemblerX64::Fail() {
   ASSERT(FAILURE == 0);  // Return value for failure is zero.
-  __ xor_(rax, rax);  // zero rax.
+  __ Set(rax, 0);
   __ jmp(&exit_label_);
 }