[turbofan] Introduce TruncateTaggedToWord32 simplified operator.

src/builtins.cc

 // Copyright 2012 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/builtins.h"
 
 #include "src/api-arguments.h"
 #include "src/api-natives.h"
 #include "src/api.h"
 #include "src/base/once.h"
@@ skipping 5203 matching lines @@
 
   a->Bind(&if_numberissmi);
   {
     var_result.Bind(a->SmiToWord32(number_index));
     a->Goto(&done);
   }
 
   a->Bind(&if_numberisnotsmi);
   {
     Node* number_index_value = a->LoadHeapNumberValue(number_index);
-    Node* access_index = a->TruncateFloat64ToInt32(number_index_value);
+    Node* access_index = a->TruncateFloat64ToWord32(number_index_value);
     Node* test_index = a->ChangeInt32ToFloat64(access_index);
 
     CodeStubAssembler::Label if_indexesareequal(a), if_indexesarenotequal(a);
     a->Branch(a->Float64Equal(number_index_value, test_index),
               &if_indexesareequal, &if_indexesarenotequal);
 
     a->Bind(&if_indexesareequal);
     {
       var_result.Bind(access_index);
       a->Goto(&done);
@@ skipping 111 matching lines @@
 BUILTIN_LIST_T(DEFINE_BUILTIN_ACCESSOR_T)
 BUILTIN_LIST_H(DEFINE_BUILTIN_ACCESSOR_H)
 BUILTIN_LIST_DEBUG_A(DEFINE_BUILTIN_ACCESSOR_A)
 #undef DEFINE_BUILTIN_ACCESSOR_C
 #undef DEFINE_BUILTIN_ACCESSOR_A
 #undef DEFINE_BUILTIN_ACCESSOR_T
 #undef DEFINE_BUILTIN_ACCESSOR_H
 
 }  // namespace internal
 }  // namespace v8