Support symbol comparison in crankshaft.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index a850ecf5fcb0e785351b5166eb638160c629e5a9..a4858abba583bbb317cd85467d0823f8508a7e29 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -1107,6 +1107,10 @@ LInstruction* LChunkBuilder::DoTest(HTest* instr) {
       HCompareJSObjectEq* compare = HCompareJSObjectEq::cast(v);
       return new LCmpJSObjectEqAndBranch(UseRegisterAtStart(compare->left()),
                                          UseRegisterAtStart(compare->right()));
+    } else if (v->IsCompareSymbolEq()) {
+      HCompareSymbolEq* compare = HCompareSymbolEq::cast(v);
+      return new LCmpSymbolEqAndBranch(UseRegisterAtStart(compare->left()),
+                                       UseRegisterAtStart(compare->right()));
     } else if (v->IsInstanceOf()) {
       HInstanceOf* instance_of = HInstanceOf::cast(v);
       LInstanceOfAndBranch* result =
@@ -1514,6 +1518,15 @@ LInstruction* LChunkBuilder::DoCompareJSObjectEq(
 }
 
 
+LInstruction* LChunkBuilder::DoCompareSymbolEq(
+    HCompareSymbolEq* instr) {
+  LOperand* left = UseRegisterAtStart(instr->left());
+  LOperand* right = UseRegisterAtStart(instr->right());
+  LCmpSymbolEq* result = new LCmpSymbolEq(left, right);
+  return DefineAsRegister(result);
+}
+
+
 LInstruction* LChunkBuilder::DoIsNull(HIsNull* instr) {
   ASSERT(instr->value()->representation().IsTagged());
   LOperand* value = UseRegisterAtStart(instr->value());