Add lithium support for %_GetCachedArrayIndex for IA32 and X64

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
===================================================================
--- src/x64/lithium-codegen-x64.cc	(revision 7028)
+++ src/x64/lithium-codegen-x64.cc	(working copy)
@@ -1631,6 +1631,20 @@
 }
 
 
+void LCodeGen::DoGetCachedArrayIndex(LGetCachedArrayIndex* instr) {
+  Register input = ToRegister(instr->InputAt(0));
+  Register result = ToRegister(instr->result());
+
+  if (FLAG_debug_code) {
+    __ AbortIfNotString(input);
+  }
+
+  __ movl(result, FieldOperand(input, String::kHashFieldOffset));
+  ASSERT(String::kHashShift >= kSmiTagSize);
+  __ IndexFromHash(result, result);
+}
+
+
 void LCodeGen::DoHasCachedArrayIndex(LHasCachedArrayIndex* instr) {
   Register input = ToRegister(instr->InputAt(0));
   Register result = ToRegister(instr->result());
@@ -1640,7 +1654,7 @@
   __ testl(FieldOperand(input, String::kHashFieldOffset),
            Immediate(String::kContainsCachedArrayIndexMask));
   NearLabel done;
-  __ j(not_zero, &done);
+  __ j(zero, &done);
   __ LoadRoot(result, Heap::kFalseValueRootIndex);
   __ bind(&done);
 }
@@ -1655,7 +1669,7 @@
 
   __ testl(FieldOperand(input, String::kHashFieldOffset),
            Immediate(String::kContainsCachedArrayIndexMask));
-  EmitBranch(true_block, false_block, not_equal);
+  EmitBranch(true_block, false_block, equal);
 }