[turbofan] Correctify representation changes to bit.

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 9d45e5b19261c39f5492687aa828588b3a63054c..01ad15e21eff01ac4c22306e6efde18618225674 100644
--- a/src/compiler/simplified-operator-reducer.cc
+++ b/src/compiler/simplified-operator-reducer.cc
@@ -54,6 +54,8 @@ Reduction SimplifiedOperatorReducer::Reduce(Node* node) {
       if (m.IsChangeBitToBool()) return Replace(m.node()->InputAt(0));
       break;
     }
+    case IrOpcode::kChangeWord32ToBit:
+      return ReduceChangeWord32ToBit(node);
     case IrOpcode::kChangeFloat64ToTagged: {
       Float64Matcher m(node->InputAt(0));
       if (m.HasValue()) return ReplaceNumber(m.Value());
@@ -136,6 +138,17 @@ Reduction SimplifiedOperatorReducer::ReduceAnyToBoolean(Node* node) {
 }
 
 
+Reduction SimplifiedOperatorReducer::ReduceChangeWord32ToBit(Node* node) {
+  Node* const input = NodeProperties::GetValueInput(node, 0);
+  Type* const input_type = NodeProperties::GetBounds(input).upper;
+  if (input_type->Is(jsgraph()->ZeroOneRangeType())) {
+    // ChangeWord32ToBit(x:bit) => x
+    return Replace(input);
+  }
+  return NoChange();
+}
+
+
 Reduction SimplifiedOperatorReducer::Change(Node* node, const Operator* op,
                                             Node* a) {
   DCHECK_EQ(node->InputCount(), OperatorProperties::GetTotalInputCount(op));