Revert revision 5657.

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

Index: src/x64/regexp-macro-assembler-x64.cc
diff --git a/src/x64/regexp-macro-assembler-x64.cc b/src/x64/regexp-macro-assembler-x64.cc
index fa0e642e5eb815fd379cd07f9df6da28d0de3a66..91e2b449e015fe0ec42ad2c113a2c95c44864dcc 100644
--- a/src/x64/regexp-macro-assembler-x64.cc
+++ b/src/x64/regexp-macro-assembler-x64.cc
@@ -145,6 +145,7 @@ int RegExpMacroAssemblerX64::stack_limit_slack()  {
 
 void RegExpMacroAssemblerX64::AdvanceCurrentPosition(int by) {
   if (by != 0) {
+    Label inside_string;
     __ addq(rdi, Immediate(by * char_size()));
   }
 }
@@ -1052,19 +1053,6 @@ void RegExpMacroAssemblerX64::ReadStackPointerFromRegister(int reg) {
 }
 
 
-void RegExpMacroAssemblerX64::SetCurrentPositionFromEnd(int by) {
-  NearLabel after_position;
-  __ cmpq(rdi, Immediate(-by * char_size()));
-  __ j(above_equal, &after_position);
-  __ movq(rdi, Immediate(-by * char_size()));
-  // On RegExp code entry (where this operation is used), the character before
-  // the current position is expected to be already loaded.
-  // We have advenced the position, so it's safe to read backwards.
-  LoadCurrentCharacterUnchecked(-1, 1);
-  __ bind(&after_position);
-}
-
-
 void RegExpMacroAssemblerX64::SetRegister(int register_index, int to) {
   ASSERT(register_index >= num_saved_registers_);  // Reserved for positions!
   __ movq(register_location(register_index), Immediate(to));