[turbofan] Introduce TruncateTaggedToWord32 simplified operator.

src/compiler/change-lowering.h

 // 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.
 
 #ifndef V8_COMPILER_CHANGE_LOWERING_H_
 #define V8_COMPILER_CHANGE_LOWERING_H_
 
 #include "src/compiler/graph-reducer.h"
 
 namespace v8 {
@@ skipping 33 matching lines @@
   Reduction ChangeBitToBool(Node* value, Node* control);
   Reduction ChangeBoolToBit(Node* value);
   Reduction ChangeFloat64ToTagged(Node* value, Node* control);
   Reduction ChangeInt31ToTagged(Node* value, Node* control);
   Reduction ChangeInt32ToTagged(Node* value, Node* control);
   Reduction ChangeTaggedSignedToInt32(Node* value);
   Reduction ChangeTaggedToFloat64(Node* value, Node* control);
   Reduction ChangeTaggedToUI32(Node* value, Node* control,
                                Signedness signedness);
   Reduction ChangeUint32ToTagged(Node* value, Node* control);
+  Reduction TruncateTaggedToWord32(Node* value, Node* control);
 
   Reduction LoadField(Node* node);
   Reduction StoreField(Node* node);
   Reduction LoadElement(Node* node);
   Reduction StoreElement(Node* node);
   Reduction Allocate(Node* node);
 
   Node* IsSmi(Node* value);
   Node* LoadHeapObjectMap(Node* object, Node* control);
   Node* LoadMapBitField(Node* map);
@@ skipping 15 matching lines @@
 
   JSGraph* const jsgraph_;
   SetOncePointer<const Operator> allocate_heap_number_operator_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_CHANGE_LOWERING_H_