[turbofan] Introduce simplified operator NumberAbs.

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 73 matching lines @@
 
  private:
   Node* node_;
 };
 
 JSBuiltinReducer::JSBuiltinReducer(Editor* editor, JSGraph* jsgraph)
     : AdvancedReducer(editor),
       jsgraph_(jsgraph),
       type_cache_(TypeCache::Get()) {}
 
+// ES6 section 20.2.2.1 Math.abs ( x )
+Reduction JSBuiltinReducer::ReduceMathAbs(Node* node) {
+  JSCallReduction r(node);
+  if (r.InputsMatchOne(Type::PlainPrimitive())) {
+    // Math.abs(a:plain-primitive) -> NumberAbs(ToNumber(a))
+    Node* input = ToNumber(r.GetJSCallInput(0));
+    Node* value = graph()->NewNode(simplified()->NumberAbs(), input);
+    return Replace(value);
+  }
+  return NoChange();
+}
+
 // ES6 section 20.2.2.6 Math.atan ( x )
 Reduction JSBuiltinReducer::ReduceMathAtan(Node* node) {
   JSCallReduction r(node);
   if (r.InputsMatchOne(Type::PlainPrimitive())) {
     // Math.atan(a:plain-primitive) -> NumberAtan(ToNumber(a))
     Node* input = ToNumber(r.GetJSCallInput(0));
     Node* value = graph()->NewNode(simplified()->NumberAtan(), input);
     return Replace(value);
   }
   return NoChange();
@@ skipping 306 matching lines @@
   return NoChange();
 }
 
 Reduction JSBuiltinReducer::Reduce(Node* node) {
   Reduction reduction = NoChange();
   JSCallReduction r(node);
 
   // Dispatch according to the BuiltinFunctionId if present.
   if (!r.HasBuiltinFunctionId()) return NoChange();
   switch (r.GetBuiltinFunctionId()) {
+    case kMathAbs:
+      reduction = ReduceMathAbs(node);
+      break;
     case kMathAtan:
       reduction = ReduceMathAtan(node);
       break;
     case kMathAtan2:
       reduction = ReduceMathAtan2(node);
       break;
     case kMathAtanh:
       reduction = ReduceMathAtanh(node);
       break;
     case kMathClz32:
@@ skipping 94 matching lines @@
 }
 
 
 SimplifiedOperatorBuilder* JSBuiltinReducer::simplified() const {
   return jsgraph()->simplified();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8