PPC: [stubs] Refactor StringCompareStub and use it for HStringCompareAndBranch.

src/ppc/lithium-codegen-ppc.cc

Index: src/ppc/lithium-codegen-ppc.cc
diff --git a/src/ppc/lithium-codegen-ppc.cc b/src/ppc/lithium-codegen-ppc.cc
index 6360252c1ea4eaa26da04a13fc499f2920a3f7e9..92c75e4d8fd0b07ed885a142ebddee94e3f3ed1c 100644
--- a/src/ppc/lithium-codegen-ppc.cc
+++ b/src/ppc/lithium-codegen-ppc.cc
@@ -984,11 +984,6 @@ 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();
   }
@@ -2610,17 +2605,14 @@ static Condition ComputeCompareCondition(Token::Value op) {
 
 void LCodeGen::DoStringCompareAndBranch(LStringCompareAndBranch* instr) {
   DCHECK(ToRegister(instr->context()).is(cp));
-  Token::Value op = instr->op();
+  DCHECK(ToRegister(instr->left()).is(r4));
+  DCHECK(ToRegister(instr->right()).is(r3));
 
-  Handle<Code> ic =
-      CodeFactory::CompareIC(isolate(), op, Strength::WEAK).code();
-  CallCode(ic, RelocInfo::CODE_TARGET, instr);
-  // This instruction also signals no smi code inlined
+  Handle<Code> code = CodeFactory::StringCompare(isolate()).code();
+  CallCode(code, RelocInfo::CODE_TARGET, instr);
   __ cmpi(r3, Operand::Zero());
 
-  Condition condition = ComputeCompareCondition(op);
-
-  EmitBranch(instr, condition);
+  EmitBranch(instr, ComputeCompareCondition(instr->op()));
 }