[builtins] Introduce proper Float64Exp operator.

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

 // Copyright 2012 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/arm/lithium-codegen-arm.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/crankshaft/arm/lithium-gap-resolver-arm.h"
@@ skipping 3522 matching lines @@
     __ CallStub(&stub);
   } else {
     DCHECK(exponent_type.IsDouble());
     MathPowStub stub(isolate(), MathPowStub::DOUBLE);
     __ CallStub(&stub);
   }
 }
 
 
 void LCodeGen::DoMathExp(LMathExp* instr) {
-  DwVfpRegister input = ToDoubleRegister(instr->value());
-  DwVfpRegister result = ToDoubleRegister(instr->result());
-  DwVfpRegister double_scratch1 = ToDoubleRegister(instr->double_temp());
-  DwVfpRegister double_scratch2 = double_scratch0();
-  Register temp1 = ToRegister(instr->temp1());
-  Register temp2 = ToRegister(instr->temp2());
-
-  MathExpGenerator::EmitMathExp(
-      masm(), input, result, double_scratch1, double_scratch2,
-      temp1, temp2, scratch0());
+  __ PrepareCallCFunction(0, 1, scratch0());
+  __ MovToFloatParameter(ToDoubleRegister(instr->value()));
+  __ CallCFunction(ExternalReference::ieee754_exp_function(isolate()), 0, 1);
+  __ MovFromFloatResult(ToDoubleRegister(instr->result()));
 }
 
 
 void LCodeGen::DoMathLog(LMathLog* instr) {
   __ PrepareCallCFunction(0, 1, scratch0());
   __ MovToFloatParameter(ToDoubleRegister(instr->value()));
   __ CallCFunction(ExternalReference::ieee754_log_function(isolate()), 0, 1);
   __ MovFromFloatResult(ToDoubleRegister(instr->result()));
 }
 
@@ skipping 1987 matching lines @@
   __ ldr(result, FieldMemOperand(scratch,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8