[turbofan] Avoid generating dead BooleanNot nodes in typed lowering.

src/compiler/js-typed-lowering.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/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/operator-properties.h"
@@ skipping 498 matching lines @@
 
 
 Reduction JSTypedLowering::ReduceJSUnaryNot(Node* node) {
   Node* input = node->InputAt(0);
   Type* input_type = NodeProperties::GetBounds(input).upper;
   if (input_type->Is(Type::Boolean())) {
     // JSUnaryNot(x:boolean,context) => BooleanNot(x)
     node->set_op(simplified()->BooleanNot());
     node->TrimInputCount(1);
     return Changed(node);
+  } else if (input_type->Is(Type::OrderedNumber())) {
+    // JSUnaryNot(x:number,context) => NumberEqual(x,#0)
+    node->set_op(simplified()->NumberEqual());
+    node->ReplaceInput(1, jsgraph()->ZeroConstant());
+    DCHECK_EQ(2, node->InputCount());
+    return Changed(node);
   }
   // JSUnaryNot(x,context) => BooleanNot(AnyToBoolean(x))
   node->set_op(simplified()->BooleanNot());
   node->ReplaceInput(0, graph()->NewNode(simplified()->AnyToBoolean(), input));
   node->TrimInputCount(1);
   return Changed(node);
 }
 
 
 Reduction JSTypedLowering::ReduceJSToBoolean(Node* node) {
@@ skipping 495 matching lines @@
 }
 
 
 MachineOperatorBuilder* JSTypedLowering::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8