Revert of [builtins] Introduce proper Float64Exp operator.

src/compiler/js-builtin-reducer.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/compiler/js-builtin-reducer.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/simplified-operator.h"
 #include "src/objects-inl.h"
@@ skipping 122 matching lines @@
 // ES6 section 20.2.2.11 Math.clz32 ( x )
 Reduction JSBuiltinReducer::ReduceMathClz32(Node* node) {
   JSCallReduction r(node);
   if (r.InputsMatchOne(Type::PlainPrimitive())) {
     // Math.clz32(a:plain-primitive) -> NumberClz32(ToUint32(a))
     Node* input = ToUint32(r.GetJSCallInput(0));
     Node* value = graph()->NewNode(simplified()->NumberClz32(), input);
     return Replace(value);
   }
   return NoChange();
-}
-
-// ES6 section 20.2.2.14 Math.exp ( x )
-Reduction JSBuiltinReducer::ReduceMathExp(Node* node) {
-  JSCallReduction r(node);
-  if (r.InputsMatchOne(Type::PlainPrimitive())) {
-    // Math.exp(a:plain-primitive) -> NumberExp(ToNumber(a))
-    Node* input = ToNumber(r.GetJSCallInput(0));
-    Node* value = graph()->NewNode(simplified()->NumberExp(), input);
-    return Replace(value);
-  }
-  return NoChange();
 }
 
 // ES6 section 20.2.2.16 Math.floor ( x )
 Reduction JSBuiltinReducer::ReduceMathFloor(Node* node) {
   JSCallReduction r(node);
   if (r.InputsMatchOne(Type::PlainPrimitive())) {
     // Math.floor(a:plain-primitive) -> NumberFloor(ToNumber(a))
     Node* input = ToNumber(r.GetJSCallInput(0));
     Node* value = graph()->NewNode(simplified()->NumberFloor(), input);
     return Replace(value);
@@ skipping 188 matching lines @@
       break;
     case kMathAtan2:
       reduction = ReduceMathAtan2(node);
       break;
     case kMathClz32:
       reduction = ReduceMathClz32(node);
       break;
     case kMathCeil:
       reduction = ReduceMathCeil(node);
       break;
-    case kMathExp:
-      reduction = ReduceMathExp(node);
-      break;
     case kMathFloor:
       reduction = ReduceMathFloor(node);
       break;
     case kMathFround:
       reduction = ReduceMathFround(node);
       break;
     case kMathImul:
       reduction = ReduceMathImul(node);
       break;
     case kMathLog:
@@ skipping 61 matching lines @@
 }
 
 
 SimplifiedOperatorBuilder* JSBuiltinReducer::simplified() const {
   return jsgraph()->simplified();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8