[turbofan] Introduce dedicated NumberToBoolean operator.

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/js-typed-lowering.h"
 
 #include "src/builtins/builtins-utils.h"
 #include "src/code-factory.h"
 #include "src/compilation-dependencies.h"
 #include "src/compiler/access-builder.h"
@@ skipping 759 matching lines @@
     return Replace(input);
   } else if (input_type->Is(Type::OrderedNumber())) {
     // JSToBoolean(x:ordered-number) => BooleanNot(NumberEqual(x,#0))
     RelaxEffectsAndControls(node);
     node->ReplaceInput(0, graph()->NewNode(simplified()->NumberEqual(), input,
                                            jsgraph()->ZeroConstant()));
     node->TrimInputCount(1);
     NodeProperties::ChangeOp(node, simplified()->BooleanNot());
     return Changed(node);
   } else if (input_type->Is(Type::Number())) {
-    // JSToBoolean(x:number) => NumberLessThan(#0,NumberAbs(x))
+    // JSToBoolean(x:number) => NumberToBoolean(x)
     RelaxEffectsAndControls(node);
-    node->ReplaceInput(0, jsgraph()->ZeroConstant());
-    node->ReplaceInput(1, graph()->NewNode(simplified()->NumberAbs(), input));
-    node->TrimInputCount(2);
-    NodeProperties::ChangeOp(node, simplified()->NumberLessThan());
+    node->TrimInputCount(1);
+    NodeProperties::ChangeOp(node, simplified()->NumberToBoolean());
     return Changed(node);
   } else if (input_type->Is(Type::String())) {
     // JSToBoolean(x:string) => NumberLessThan(#0,x.length)
     FieldAccess const access = AccessBuilder::ForStringLength();
     Node* length = graph()->NewNode(simplified()->LoadField(access), input,
                                     graph()->start(), graph()->start());
     ReplaceWithValue(node, node, length);
     node->ReplaceInput(0, jsgraph()->ZeroConstant());
     node->ReplaceInput(1, length);
     NodeProperties::ChangeOp(node, simplified()->NumberLessThan());
@@ skipping 1212 matching lines @@
 }
 
 
 CompilationDependencies* JSTypedLowering::dependencies() const {
   return dependencies_;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8