Revert of [builtins] Introduce proper Float64Exp operator.

src/compiler/machine-operator.h

 // Copyright 2013 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.
 
 #ifndef V8_COMPILER_MACHINE_OPERATOR_H_
 #define V8_COMPILER_MACHINE_OPERATOR_H_
 
 #include "src/base/flags.h"
 #include "src/machine-type.h"
 
@@ skipping 354 matching lines @@
   const OptionalOperator Float64RoundTiesEven();
 
   // Floating point neg.
   const OptionalOperator Float32Neg();
   const OptionalOperator Float64Neg();
 
   // Floating point trigonometric functions (double-precision).
   const Operator* Float64Atan();
   const Operator* Float64Atan2();
 
-  // Floating point exponential functions.
-  const Operator* Float64Exp();
-
   // Floating point logarithm (double-precision).
   const Operator* Float64Log();
   const Operator* Float64Log1p();
   const Operator* Float64Log2();
   const Operator* Float64Log10();
 
   // Floating point bit representation.
   const Operator* Float64ExtractLowWord32();
   const Operator* Float64ExtractHighWord32();
   const Operator* Float64InsertLowWord32();
@@ skipping 268 matching lines @@
 };
 
 
 DEFINE_OPERATORS_FOR_FLAGS(MachineOperatorBuilder::Flags)
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_MACHINE_OPERATOR_H_