[turbofan] Introduce a SpeculativeToNumber operator.

src/compiler/typed-optimization.cc

 // Copyright 2016 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/typed-optimization.h"
 
 #include "src/compilation-dependencies.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/simplified-operator.h"
@@ skipping 78 matching lines @@
     case IrOpcode::kNumberFloor:
       return ReduceNumberFloor(node);
     case IrOpcode::kNumberToUint8Clamped:
       return ReduceNumberToUint8Clamped(node);
     case IrOpcode::kPhi:
       return ReducePhi(node);
     case IrOpcode::kReferenceEqual:
       return ReduceReferenceEqual(node);
     case IrOpcode::kSelect:
       return ReduceSelect(node);
+    case IrOpcode::kSpeculativeToNumber:
+      return ReduceSpeculativeToNumber(node);
     default:
       break;
   }
   return NoChange();
 }
 
 namespace {
 
 MaybeHandle<Map> GetStableMapFromObjectType(Type* object_type) {
   if (object_type->IsHeapConstant()) {
@@ skipping 195 matching lines @@
   Type* type = Type::Union(vtrue_type, vfalse_type, graph()->zone());
   Type* const node_type = NodeProperties::GetType(node);
   if (!node_type->Is(type)) {
     type = Type::Intersect(node_type, type, graph()->zone());
     NodeProperties::SetType(node, type);
     return Changed(node);
   }
   return NoChange();
 }
 
+Reduction TypedOptimization::ReduceSpeculativeToNumber(Node* node) {
+  DCHECK_EQ(IrOpcode::kSpeculativeToNumber, node->opcode());
+  Node* const input = NodeProperties::GetValueInput(node, 0);
+  Type* const input_type = NodeProperties::GetType(input);
+  if (input_type->Is(Type::Number())) {
+    // SpeculativeToNumber(x:number) => x
+    ReplaceWithValue(node, input);
+    return Replace(input);
+  }
+  return NoChange();
+}
+
 Factory* TypedOptimization::factory() const { return isolate()->factory(); }
 
 Graph* TypedOptimization::graph() const { return jsgraph()->graph(); }
 
 Isolate* TypedOptimization::isolate() const { return jsgraph()->isolate(); }
 
 SimplifiedOperatorBuilder* TypedOptimization::simplified() const {
   return jsgraph()->simplified();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8