[turbofan] Move more type checks to the representation selector.

src/compiler/simplified-operator-reducer.cc

Index: src/compiler/simplified-operator-reducer.cc
diff --git a/src/compiler/simplified-operator-reducer.cc b/src/compiler/simplified-operator-reducer.cc
index 8a7180e40ba12aeeb47de878b002611567ea789d..1a5b267b415f22f968192589ad72d38708e7eaed 100644
--- a/src/compiler/simplified-operator-reducer.cc
+++ b/src/compiler/simplified-operator-reducer.cc
@@ -54,6 +54,9 @@ Reduction SimplifiedOperatorReducer::Reduce(Node* node) {
     case IrOpcode::kChangeInt32ToTagged: {
       Int32Matcher m(node->InputAt(0));
       if (m.HasValue()) return ReplaceNumber(m.Value());
+      if (m.IsChangeTaggedToInt32() || m.IsChangeTaggedSignedToInt32()) {
+        return Replace(m.InputAt(0));
+      }
       break;
     }
     case IrOpcode::kChangeTaggedToFloat64: {