Support symbol comparison in crankshaft.

src/ia32/lithium-ia32.h

Index: src/ia32/lithium-ia32.h
diff --git a/src/ia32/lithium-ia32.h b/src/ia32/lithium-ia32.h
index 8a93bda4e2a6743147a5efcb320b66d92dcb4f85..9eec9fdf3f536d293d352e42db7811d43a6e2384 100644
--- a/src/ia32/lithium-ia32.h
+++ b/src/ia32/lithium-ia32.h
@@ -73,6 +73,8 @@ class LCodeGen;
   V(CmpIDAndBranch)                             \
   V(CmpJSObjectEq)                              \
   V(CmpJSObjectEqAndBranch)                     \
+  V(CmpSymbolEq)                                \
+  V(CmpSymbolEqAndBranch)                       \
   V(CmpMapAndBranch)                            \
   V(CmpT)                                       \
   V(CmpTAndBranch)                              \
@@ -666,6 +668,28 @@ class LCmpJSObjectEqAndBranch: public LControlInstruction<2, 0> {
 };
 
 
+class LCmpSymbolEq: public LTemplateInstruction<1, 2, 0> {
+ public:
+  LCmpSymbolEq(LOperand* left, LOperand* right) {
+    inputs_[0] = left;
+    inputs_[1] = right;
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(CmpSymbolEq, "cmp-symbol-eq")
+};
+
+
+class LCmpSymbolEqAndBranch: public LControlInstruction<2, 0> {
+ public:
+  LCmpSymbolEqAndBranch(LOperand* left, LOperand* right) {
+    inputs_[0] = left;
+    inputs_[1] = right;
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(CmpSymbolEqAndBranch, "cmp-symbol-eq-and-branch")
+};
+
+
 class LIsNull: public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LIsNull(LOperand* value) {