[turbofan] Revive the useful parts of the SimplifiedOperatorReducer.

src/compiler/simplified-operator-reducer.h

Index: src/compiler/simplified-operator-reducer.h
diff --git a/src/compiler/js-builtin-reducer.h b/src/compiler/simplified-operator-reducer.h
similarity index 50%
copy from src/compiler/js-builtin-reducer.h
copy to src/compiler/simplified-operator-reducer.h
index 66b5723246c9e83a614a79f900d17a448b575a72..c302250d266fbea3c922962f979f4d6325669860 100644
--- a/src/compiler/js-builtin-reducer.h
+++ b/src/compiler/simplified-operator-reducer.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef V8_COMPILER_JS_BUILTIN_REDUCER_H_
-#define V8_COMPILER_JS_BUILTIN_REDUCER_H_
+#ifndef V8_COMPILER_SIMPLIFIED_OPERATOR_REDUCER_H_
+#define V8_COMPILER_SIMPLIFIED_OPERATOR_REDUCER_H_
 
 #include "src/compiler/graph-reducer.h"
 #include "src/compiler/simplified-operator.h"
@@ -13,35 +13,40 @@ namespace internal {
 namespace compiler {
 
 // Forward declarations.
-class CommonOperatorBuilder;
 class JSGraph;
 class MachineOperatorBuilder;
 
 
-class JSBuiltinReducer final : public AdvancedReducer {
+class SimplifiedOperatorReducer final : public Reducer {
  public:
-  explicit JSBuiltinReducer(Editor* editor, JSGraph* jsgraph);
-  ~JSBuiltinReducer() final {}
+  explicit SimplifiedOperatorReducer(JSGraph* jsgraph);
+  ~SimplifiedOperatorReducer() final;
 
   Reduction Reduce(Node* node) final;
 
  private:
-  Reduction ReduceMathMax(Node* node);
-  Reduction ReduceMathImul(Node* node);
-  Reduction ReduceMathFround(Node* node);
+  Reduction Change(Node* node, const Operator* op, Node* a);
+  Reduction ReplaceFloat64(double value);
+  Reduction ReplaceInt32(int32_t value);
+  Reduction ReplaceUint32(uint32_t value) {
+    return ReplaceInt32(bit_cast<int32_t>(value));
+  }
+  Reduction ReplaceNumber(double value);
+  Reduction ReplaceNumber(int32_t value);
 
-  JSGraph* jsgraph() const { return jsgraph_; }
   Graph* graph() const;
-  CommonOperatorBuilder* common() const;
+  JSGraph* jsgraph() const { return jsgraph_; }
   MachineOperatorBuilder* machine() const;
   SimplifiedOperatorBuilder* simplified() { return &simplified_; }
 
-  JSGraph* jsgraph_;
+  JSGraph* const jsgraph_;
   SimplifiedOperatorBuilder simplified_;
+
+  DISALLOW_COPY_AND_ASSIGN(SimplifiedOperatorReducer);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
-#endif  // V8_COMPILER_JS_BUILTIN_REDUCER_H_
+#endif  // V8_COMPILER_SIMPLIFIED_OPERATOR_REDUCER_H_