Revert of [builtins] Introduce proper Float64Exp operator.

src/crankshaft/mips64/lithium-codegen-mips64.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/mips64/lithium-codegen-mips64.h"
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/crankshaft/hydrogen-osr.h"
 #include "src/crankshaft/mips64/lithium-gap-resolver-mips64.h"
@@ skipping 3677 matching lines @@
     __ CallStub(&stub);
   } else {
     DCHECK(exponent_type.IsDouble());
     MathPowStub stub(isolate(), MathPowStub::DOUBLE);
     __ CallStub(&stub);
   }
 }
 
 
 void LCodeGen::DoMathExp(LMathExp* instr) {
-  __ PrepareCallCFunction(0, 1, scratch0());
-  __ MovToFloatParameter(ToDoubleRegister(instr->value()));
-  __ CallCFunction(ExternalReference::ieee754_exp_function(isolate()), 0, 1);
-  __ MovFromFloatResult(ToDoubleRegister(instr->result()));
+  DoubleRegister input = ToDoubleRegister(instr->value());
+  DoubleRegister result = ToDoubleRegister(instr->result());
+  DoubleRegister double_scratch1 = ToDoubleRegister(instr->double_temp());
+  DoubleRegister 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());
 }
 
 
 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 2033 matching lines @@
   __ ld(result, FieldMemOperand(scratch,
                                 FixedArray::kHeaderSize - kPointerSize));
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8