[turbofan] Use builtin inlining mechanism for Math.floor.

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/diamond.h"
 #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/types.h"
@@ skipping 166 matching lines @@
   if (r.InputsMatchOne(Type::Number())) {
     // Math.fround(a:number) -> TruncateFloat64ToFloat32(a)
     Node* value =
         graph()->NewNode(machine()->TruncateFloat64ToFloat32(), r.left());
     return Replace(value);
   }
   return NoChange();
 }
 
 
-// ES6 draft 10-14-14, section 20.2.2.16.
-Reduction JSBuiltinReducer::ReduceMathFloor(Node* node) {
-  if (!machine()->HasFloat64RoundDown()) return NoChange();
-  JSCallReduction r(node);
-  if (r.InputsMatchOne(Type::Number())) {
-    // Math.floor(a:number) -> Float64RoundDown(a)
-    Node* value = graph()->NewNode(machine()->Float64RoundDown(), r.left());
-    return Replace(value);
-  }
-  return NoChange();
-}
-
-
 Reduction JSBuiltinReducer::Reduce(Node* node) {
   JSCallReduction r(node);
 
   // Dispatch according to the BuiltinFunctionId if present.
   if (!r.HasBuiltinFunctionId()) return NoChange();
   switch (r.GetBuiltinFunctionId()) {
     case kMathAbs:
       return ReplaceWithPureReduction(node, ReduceMathAbs(node));
     case kMathSqrt:
       return ReplaceWithPureReduction(node, ReduceMathSqrt(node));
     case kMathMax:
       return ReplaceWithPureReduction(node, ReduceMathMax(node));
     case kMathImul:
       return ReplaceWithPureReduction(node, ReduceMathImul(node));
     case kMathFround:
       return ReplaceWithPureReduction(node, ReduceMathFround(node));
-    case kMathFloor:
-      return ReplaceWithPureReduction(node, ReduceMathFloor(node));
     default:
       break;
   }
   return NoChange();
 }
 
 
 Graph* JSBuiltinReducer::graph() const { return jsgraph()->graph(); }
 
 
 CommonOperatorBuilder* JSBuiltinReducer::common() const {
   return jsgraph()->common();
 }
 
 
 MachineOperatorBuilder* JSBuiltinReducer::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8