[turbofan] Improve representation selection for Smi checking.

src/compiler/js-builtin-reducer.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-builtin-reducer.h"
 
 #include "src/compilation-dependencies.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-matchers.h"
@@ skipping 257 matching lines @@
 
     // TODO(turbofan): Perform type checks on the {value}. We are not guaranteed
     // to learn from these checks in case they fail, as the witness (i.e. the
     // map check from the LoadIC for a.push) might not be executed in baseline
     // code (after we stored the value in the builtin and thereby changed the
     // elements kind of a) before be decide to optimize this function again. We
     // currently don't have a proper way to deal with this; the proper solution
     // here is to learn on deopt, i.e. disable Array.prototype.push inlining
     // for this function.
     if (IsFastSmiElementsKind(receiver_map->elements_kind())) {
-      value = effect = graph()->NewNode(simplified()->CheckTaggedSigned(),
-                                        value, effect, control);
+      value = effect =
+          graph()->NewNode(simplified()->CheckSmi(), value, effect, control);
     } else if (IsFastDoubleElementsKind(receiver_map->elements_kind())) {
       value = effect =
           graph()->NewNode(simplified()->CheckNumber(), value, effect, control);
       // Make sure we do not store signaling NaNs into double arrays.
       value = graph()->NewNode(simplified()->NumberSilenceNaN(), value);
     }
 
     // Load the "length" property of the {receiver}.
     Node* length = effect = graph()->NewNode(
         simplified()->LoadField(
@@ skipping 960 matching lines @@
 }
 
 
 SimplifiedOperatorBuilder* JSBuiltinReducer::simplified() const {
   return jsgraph()->simplified();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8