[turbofan] Handle word32 truncation in word32->tagged representation change.

src/compiler/simplified-lowering.cc

Index: src/compiler/simplified-lowering.cc
diff --git a/src/compiler/simplified-lowering.cc b/src/compiler/simplified-lowering.cc
index 1eadfb7b523e68fb46df4dd3eaef65df9bd9fd58..8a7513d101781d6883185f9e384669552ecb9119 100644
--- a/src/compiler/simplified-lowering.cc
+++ b/src/compiler/simplified-lowering.cc
@@ -929,9 +929,6 @@ class RepresentationSelector {
     }
     // Convert inputs to the output representation of this phi, pass the
     // truncation truncation along.
-    if (output == MachineRepresentation::kTagged) {
-      truncation = Truncation::Any();
-    }
     UseInfo input_use(output, truncation);
     ProcessInput(node, 1, input_use);
     ProcessInput(node, 2, input_use);
@@ -956,9 +953,6 @@ class RepresentationSelector {
 
     // Convert inputs to the output representation of this phi, pass the
     // truncation along.
-    if (output == MachineRepresentation::kTagged) {
-      truncation = Truncation::Any();
-    }
     UseInfo input_use(output, truncation);
     for (int i = 0; i < node->InputCount(); i++) {
       ProcessInput(node, i, i < values ? input_use : UseInfo::None());
@@ -2446,10 +2440,6 @@ class RepresentationSelector {
         // the sigma's type.
         MachineRepresentation output =
             GetOutputInfoForPhi(node, TypeOf(node->InputAt(0)), truncation);
-
-        if (output == MachineRepresentation::kTagged) {
-          truncation = Truncation::Any();
-        }
         VisitUnop(node, UseInfo(output, truncation), output);
         if (lower()) DeferReplacement(node, node->InputAt(0));
         return;