[stubs] Refactor StringCompareStub and use it for HStringCompareAndBranch.

src/arm64/lithium-codegen-arm64.cc

Index: src/arm64/lithium-codegen-arm64.cc
diff --git a/src/arm64/lithium-codegen-arm64.cc b/src/arm64/lithium-codegen-arm64.cc
index e256ed0b0aed32c78e8a79e8aaa5c08d871e8716..488e14f82c5b7ba974f099fddeb7344c9648583f 100644
--- a/src/arm64/lithium-codegen-arm64.cc
+++ b/src/arm64/lithium-codegen-arm64.cc
@@ -2098,11 +2098,6 @@ void LCodeGen::DoCallStub(LCallStub* instr) {
       CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
       break;
     }
-    case CodeStub::StringCompare: {
-      StringCompareStub stub(isolate());
-      CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
-      break;
-    }
     default:
       UNREACHABLE();
   }
@@ -5503,16 +5498,13 @@ void LCodeGen::DoDeferredStringCharFromCode(LStringCharFromCode* instr) {
 
 void LCodeGen::DoStringCompareAndBranch(LStringCompareAndBranch* instr) {
   DCHECK(ToRegister(instr->context()).is(cp));
-  Token::Value op = instr->op();
-
-  Handle<Code> ic =
-      CodeFactory::CompareIC(isolate(), op, Strength::WEAK).code();
-  CallCode(ic, RelocInfo::CODE_TARGET, instr);
-  InlineSmiCheckInfo::EmitNotInlined(masm());
+  DCHECK(ToRegister(instr->left()).is(x1));
+  DCHECK(ToRegister(instr->right()).is(x0));
 
-  Condition condition = TokenToCondition(op, false);
+  Handle<Code> code = CodeFactory::StringCompare(isolate()).code();
+  CallCode(code, RelocInfo::CODE_TARGET, instr);
 
-  EmitCompareAndBranch(instr, condition, x0, 0);
+  EmitCompareAndBranch(instr, TokenToCondition(instr->op(), false), x0, 0);
 }