[turbofan] Introduce TruncateTaggedToWord32 simplified operator.

src/compiler/machine-operator-reducer.cc

Index: src/compiler/machine-operator-reducer.cc
diff --git a/src/compiler/machine-operator-reducer.cc b/src/compiler/machine-operator-reducer.cc
index 19ea06205361fef01f29d5a2dc22e6067de10554..7271503d46fdcc4f363d0de135e8cc43b636a876 100644
--- a/src/compiler/machine-operator-reducer.cc
+++ b/src/compiler/machine-operator-reducer.cc
@@ -419,8 +419,12 @@ Reduction MachineOperatorReducer::Reduce(Node* node) {
       if (m.HasValue()) return ReplaceInt64(static_cast<uint64_t>(m.Value()));
       break;
     }
-    case IrOpcode::kTruncateFloat64ToInt32:
-      return ReduceTruncateFloat64ToInt32(node);
+    case IrOpcode::kTruncateFloat64ToWord32: {
+      Float64Matcher m(node->InputAt(0));
+      if (m.HasValue()) return ReplaceInt32(DoubleToInt32(m.Value()));
+      if (m.IsChangeInt32ToFloat64()) return Replace(m.node()->InputAt(0));
+      return NoChange();
+    }
     case IrOpcode::kTruncateInt64ToInt32: {
       Int64Matcher m(node->InputAt(0));
       if (m.HasValue()) return ReplaceInt32(static_cast<int32_t>(m.Value()));
@@ -433,6 +437,12 @@ Reduction MachineOperatorReducer::Reduce(Node* node) {
       if (m.IsChangeFloat32ToFloat64()) return Replace(m.node()->InputAt(0));
       break;
     }
+    case IrOpcode::kRoundFloat64ToInt32: {
+      Float64Matcher m(node->InputAt(0));
+      if (m.HasValue()) return ReplaceInt32(static_cast<int32_t>(m.Value()));
+      if (m.IsChangeInt32ToFloat64()) return Replace(m.node()->InputAt(0));
+      break;
+    }
     case IrOpcode::kFloat64InsertLowWord32:
       return ReduceFloat64InsertLowWord32(node);
     case IrOpcode::kFloat64InsertHighWord32:
@@ -645,37 +655,6 @@ Reduction MachineOperatorReducer::ReduceUint32Mod(Node* node) {
 }
 
 
-Reduction MachineOperatorReducer::ReduceTruncateFloat64ToInt32(Node* node) {
-  Float64Matcher m(node->InputAt(0));
-  if (m.HasValue()) return ReplaceInt32(DoubleToInt32(m.Value()));
-  if (m.IsChangeInt32ToFloat64()) return Replace(m.node()->InputAt(0));
-  if (m.IsPhi()) {
-    Node* const phi = m.node();
-    DCHECK_EQ(MachineRepresentation::kFloat64, PhiRepresentationOf(phi->op()));
-    if (phi->OwnedBy(node)) {
-      // TruncateFloat64ToInt32[mode](Phi[Float64](x1,...,xn))
-      //   => Phi[Int32](TruncateFloat64ToInt32[mode](x1),
-      //                 ...,
-      //                 TruncateFloat64ToInt32[mode](xn))
-      const int value_input_count = phi->InputCount() - 1;
-      for (int i = 0; i < value_input_count; ++i) {
-        Node* input = graph()->NewNode(node->op(), phi->InputAt(i));
-        // TODO(bmeurer): Reschedule input for reduction once we have Revisit()
-        // instead of recursing into ReduceTruncateFloat64ToInt32() here.
-        Reduction reduction = ReduceTruncateFloat64ToInt32(input);
-        if (reduction.Changed()) input = reduction.replacement();
-        phi->ReplaceInput(i, input);
-      }
-      NodeProperties::ChangeOp(
-          phi,
-          common()->Phi(MachineRepresentation::kWord32, value_input_count));
-      return Replace(phi);
-    }
-  }
-  return NoChange();
-}
-
-
 Reduction MachineOperatorReducer::ReduceStore(Node* node) {
   MachineRepresentation const rep =
       StoreRepresentationOf(node->op()).representation();