[turbofan] Introduce simplified operator NumberAbs.

src/compiler/simplified-operator-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/simplified-operator-reducer.h"
 
 #include "src/compiler/js-graph.h"
 #include "src/compiler/machine-operator.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/operator-properties.h"
@@ skipping 139 matching lines @@
       switch (DecideObjectIsSmi(input)) {
         case Decision::kTrue:
           return ReplaceBoolean(true);
         case Decision::kFalse:
           return ReplaceBoolean(false);
         case Decision::kUnknown:
           break;
       }
       break;
     }
+    case IrOpcode::kNumberAbs: {
+      NumberMatcher m(node->InputAt(0));
+      if (m.HasValue()) return ReplaceNumber(std::fabs(m.Value()));
+      break;
+    }
     case IrOpcode::kNumberCeil:
     case IrOpcode::kNumberFloor:
     case IrOpcode::kNumberRound:
     case IrOpcode::kNumberTrunc: {
       Node* const input = NodeProperties::GetValueInput(node, 0);
       Type* const input_type = NodeProperties::GetType(input);
       if (input_type->Is(type_cache_.kIntegerOrMinusZeroOrNaN)) {
         return Replace(input);
       }
       break;
@@ skipping 69 matching lines @@
 Graph* SimplifiedOperatorReducer::graph() const { return jsgraph()->graph(); }
 
 
 MachineOperatorBuilder* SimplifiedOperatorReducer::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8