S390 [Crankshaft]: Use LoadPositive for MathAbs

src/crankshaft/s390/lithium-codegen-s390.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 //
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/crankshaft/s390/lithium-codegen-s390.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 3369 matching lines @@
 
     __ StoreToSafepointRegisterSlot(tmp1, result);
   }
 
   __ bind(&done);
 }
 
 void LCodeGen::EmitMathAbs(LMathAbs* instr) {
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());
-  Label done;
-  __ CmpP(input, Operand::Zero());
-  __ Move(result, input);
-  __ bge(&done, Label::kNear);
-  __ LoadComplementRR(result, result);
+  __ LoadPositiveP(result, input);
   // Deoptimize on overflow.
   DeoptimizeIf(overflow, instr, DeoptimizeReason::kOverflow, cr0);
-  __ bind(&done);
 }
 
 #if V8_TARGET_ARCH_S390X
 void LCodeGen::EmitInteger32MathAbs(LMathAbs* instr) {
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());
-  Label done;
-  __ Cmp32(input, Operand::Zero());
-  __ Move(result, input);
-  __ bge(&done, Label::kNear);
-
-  // Deoptimize on overflow.
-  __ Cmp32(input, Operand(0x80000000));
-  DeoptimizeIf(eq, instr, DeoptimizeReason::kOverflow);
-
-  __ LoadComplementRR(result, result);
-  __ bind(&done);
+  __ LoadPositive32(result, input);

[john.yan, 2016/12/21 21:03:52]

maybe more lgfr to here instead of putting in MacroAssembler?

+  DeoptimizeIf(overflow, instr, DeoptimizeReason::kOverflow);
 }
 #endif
 
 void LCodeGen::DoMathAbs(LMathAbs* instr) {
   // Class for deferred case.
   class DeferredMathAbsTaggedHeapNumber final : public LDeferredCode {
    public:
     DeferredMathAbsTaggedHeapNumber(LCodeGen* codegen, LMathAbs* instr)
         : LDeferredCode(codegen), instr_(instr) {}
     void Generate() override {
@@ skipping 2160 matching lines @@
   __ LoadP(result,
            FieldMemOperand(scratch, FixedArray::kHeaderSize - kPointerSize));
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8