[hydrogen] optimize switch with string clauses

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 38a8c18be39b58ed82e1c2fede1aa80411fd41f9..028f2a0c1bedca9da4ef2a0a838e7e6a5a9a99cf 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -1680,6 +1680,31 @@ void LCodeGen::DoIsObjectAndBranch(LIsObjectAndBranch* instr) {
 }
 
 
+Condition LCodeGen::EmitIsString(Register input,
+                                 Label* is_not_string,
+                                 Label* is_string) {
+
+  __ JumpIfSmi(input, is_not_string);
+  __ CmpObjectType(input, FIRST_NONSTRING_TYPE, rcx);
+
+  return below;
+}
+
+
+void LCodeGen::DoIsStringAndBranch(LIsStringAndBranch* instr) {
+  Register reg = ToRegister(instr->InputAt(0));
+
+  int true_block = chunk_->LookupDestination(instr->true_block_id());
+  int false_block = chunk_->LookupDestination(instr->false_block_id());
+  Label* true_label = chunk_->GetAssemblyLabel(true_block);
+  Label* false_label = chunk_->GetAssemblyLabel(false_block);
+
+  Condition true_cond = EmitIsString(reg, false_label, true_label);
+
+  EmitBranch(true_block, false_block, true_cond);
+}
+
+
 void LCodeGen::DoIsSmiAndBranch(LIsSmiAndBranch* instr) {
   int true_block = chunk_->LookupDestination(instr->true_block_id());
   int false_block = chunk_->LookupDestination(instr->false_block_id());
@@ -1711,6 +1736,21 @@ void LCodeGen::DoIsUndetectableAndBranch(LIsUndetectableAndBranch* instr) {
 }
 
 
+void LCodeGen::DoCompareGenericAndBranch(LCompareGenericAndBranch* instr) {
+  Token::Value op = instr->op();
+  int true_block = chunk_->LookupDestination(instr->true_block_id());
+  int false_block = chunk_->LookupDestination(instr->false_block_id());
+
+  Handle<Code> ic = CompareIC::GetUninitialized(op);
+  CallCode(ic, RelocInfo::CODE_TARGET, instr);
+
+  Condition condition = TokenToCondition(op, false);
+  __ testq(rax, rax);
+
+  EmitBranch(true_block, false_block, condition);
+}
+
+
 static InstanceType TestType(HHasInstanceTypeAndBranch* instr) {
   InstanceType from = instr->from();
   InstanceType to = instr->to();