Tag smi-constants as smi. This also fixes code that copies holes into arrays.

src/code-stubs-hydrogen.cc

Index: src/code-stubs-hydrogen.cc
diff --git a/src/code-stubs-hydrogen.cc b/src/code-stubs-hydrogen.cc
index 451b20b2e5c43502be800bcce51936d863b8619f..05af70401e9e3530dd68eea192b643c2eb7bc94c 100644
--- a/src/code-stubs-hydrogen.cc
+++ b/src/code-stubs-hydrogen.cc
@@ -670,11 +670,11 @@ HValue* CodeStubGraphBuilder<CompareNilICStub>::BuildCodeInitializedStub() {
   if_nil.Then();
   if (continuation.IsFalseReachable()) {
     if_nil.Else();
-    if_nil.Return(graph()->GetConstantSmi0());
+    if_nil.Return(graph()->GetConstant0());
   }
   if_nil.End();
   return continuation.IsTrueReachable()
-      ? graph()->GetConstantSmi1()
+      ? graph()->GetConstant1()
       : graph()->GetConstantUndefined();
 }