A64: Use the result of compare IC in StringCompareAndBranch.

src/a64/lithium-codegen-a64.cc

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@@ skipping 5090 matching lines @@
 
 void LCodeGen::DoStringCompareAndBranch(LStringCompareAndBranch* instr) {
   Token::Value op = instr->op();
 
   Handle<Code> ic = CompareIC::GetUninitialized(isolate(), op);
   CallCode(ic, RelocInfo::CODE_TARGET, instr);
   InlineSmiCheckInfo::EmitNotInlined(masm());
 
   Condition condition = TokenToCondition(op, false);
 
+  __ Tst(x0, x0);

[jbramley, 2014/02/05 13:01:41]

ARM (and AArch64) processors generally prefer "Cmp(x0, 0)". (I assume that the
condition can be either EQ or NE here.)

However, in this case, you're probably better off using EmitCompareAndBranch
because that will use Cbz or Cbnz if possible.

[ulan, 2014/02/05 13:09:21]

Done.

+
   EmitBranch(instr, condition);
 }
 
 
 void LCodeGen::DoSubI(LSubI* instr) {
   bool can_overflow = instr->hydrogen()->CheckFlag(HValue::kCanOverflow);
   Register result = ToRegister32(instr->result());
   Register left = ToRegister32(instr->left());
   Operand right = ToOperand32I(instr->right());
   if (can_overflow) {
@@ skipping 439 matching lines @@
   __ Bind(&out_of_object);
   __ Ldr(result, FieldMemOperand(object, JSObject::kPropertiesOffset));
   // Index is equal to negated out of object property index plus 1.
   __ Sub(result, result, Operand::UntagSmiAndScale(index, kPointerSizeLog2));
   __ Ldr(result, FieldMemOperand(result,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ Bind(&done);
 }
 
 } }  // namespace v8::internal