[turbofan] Address the useless overflow bit materialization.

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index bfba6f9387a74d91a73b89019e34f41b036400b2..f684dd8fae93d068b62e6031e8302bc96634a10e 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -2018,6 +2018,14 @@ Type* Typer::Visitor::TypeCheckTaggedSigned(Node* node) {
   return Type::Intersect(arg, typer_->cache_.kSmi, zone());
 }
 
+Type* Typer::Visitor::TypeCheckedInt32Add(Node* node) {
+  return Type::Integral32();
+}
+
+Type* Typer::Visitor::TypeCheckedInt32Sub(Node* node) {
+  return Type::Integral32();
+}
+
 Type* Typer::Visitor::TypeCheckedUint32ToInt32(Node* node) {
   return Type::Signed32();
 }
@@ -2057,11 +2065,6 @@ Type* Typer::Visitor::TypeCheckTaggedHole(Node* node) {
   return type;
 }
 
-Type* Typer::Visitor::TypeCheckIf(Node* node) {
-  UNREACHABLE();
-  return nullptr;
-}
-
 Type* Typer::Visitor::TypeTruncateTaggedToWord32(Node* node) {
   Type* arg = Operand(node, 0);
   // TODO(jarin): DCHECK(arg->Is(Type::NumberOrUndefined()));