[hydrogen] optimize switch with string clauses

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 0af2ce4fc46fb7e71c36b81eec8dbc26fc96eac2..fc5591dc185d11e512d7a7a45284c06240583bfc 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -230,6 +230,13 @@ void LIsObjectAndBranch::PrintDataTo(StringStream* stream) {
 }
 
 
+void LIsStringAndBranch::PrintDataTo(StringStream* stream) {
+  stream->Add("if is_string(");
+  InputAt(0)->PrintTo(stream);
+  stream->Add(") then B%d else B%d", true_block_id(), false_block_id());
+}
+
+
 void LIsSmiAndBranch::PrintDataTo(StringStream* stream) {
   stream->Add("if is_smi(");
   InputAt(0)->PrintTo(stream);
@@ -244,6 +251,14 @@ void LIsUndetectableAndBranch::PrintDataTo(StringStream* stream) {
 }
 
 
+void LCompareGenericAndBranch::PrintDataTo(StringStream* stream) {
+  stream->Add("if compare_generic(");
+  InputAt(0)->PrintTo(stream);
+  InputAt(1)->PrintTo(stream);
+  stream->Add(") then B%d else B%d", true_block_id(), false_block_id());
+}
+
+
 void LHasInstanceTypeAndBranch::PrintDataTo(StringStream* stream) {
   stream->Add("if has_instance_type(");
   InputAt(0)->PrintTo(stream);
@@ -1407,7 +1422,7 @@ LInstruction* LChunkBuilder::DoCompareGeneric(HCompareGeneric* instr) {
   LOperand* left = UseFixed(instr->left(), rdx);
   LOperand* right = UseFixed(instr->right(), rax);
   LCmpT* result = new LCmpT(left, right);
-  return MarkAsCall(DefineFixed(result, rax), instr);
+  return AssignEnvironment(MarkAsCall(DefineFixed(result, rax), instr));
 }
 
 
@@ -1465,6 +1480,12 @@ LInstruction* LChunkBuilder::DoIsObjectAndBranch(HIsObjectAndBranch* instr) {
 }
 
 
+LInstruction* LChunkBuilder::DoIsStringAndBranch(HIsStringAndBranch* instr) {
+  ASSERT(instr->value()->representation().IsTagged());
+  return new LIsStringAndBranch(UseRegisterAtStart(instr->value()));
+}
+
+
 LInstruction* LChunkBuilder::DoIsSmiAndBranch(HIsSmiAndBranch* instr) {
   ASSERT(instr->value()->representation().IsTagged());
   return new LIsSmiAndBranch(Use(instr->value()));
@@ -1479,6 +1500,19 @@ LInstruction* LChunkBuilder::DoIsUndetectableAndBranch(
 }
 
 
+LInstruction* LChunkBuilder::DoCompareGenericAndBranch(
+    HCompareGenericAndBranch* instr) {
+
+  ASSERT(instr->left()->representation().IsTagged());
+  ASSERT(instr->right()->representation().IsTagged());
+  LOperand* left = UseFixed(instr->left(), rdx);
+  LOperand* right = UseFixed(instr->right(), rax);
+  LCompareGenericAndBranch* result = new LCompareGenericAndBranch(left, right);
+
+  return AssignEnvironment(MarkAsCall(result, instr));
+}
+
+
 LInstruction* LChunkBuilder::DoHasInstanceTypeAndBranch(
     HHasInstanceTypeAndBranch* instr) {
   ASSERT(instr->value()->representation().IsTagged());