[turbofan] Proper dead code elimination as regular reducer.

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index f960153be3c02a61efa0e8b44c9057d3a8cb55ef..5417f66f27c94a7c89290149147b0df32f85d0fe 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -268,7 +268,6 @@ class Typer::Visitor : public Reducer {
       DECLARE_CASE(Terminate)
       DECLARE_CASE(OsrNormalEntry)
       DECLARE_CASE(OsrLoopEntry)
-      DECLARE_CASE(DeadControl)
       DECLARE_CASE(Throw)
       DECLARE_CASE(End)
 #undef DECLARE_CASE
@@ -313,7 +312,6 @@ class Typer::Visitor : public Reducer {
       DECLARE_CASE(Terminate)
       DECLARE_CASE(OsrNormalEntry)
       DECLARE_CASE(OsrLoopEntry)
-      DECLARE_CASE(DeadControl)
       DECLARE_CASE(Throw)
       DECLARE_CASE(End)
 #undef DECLARE_CASE
@@ -742,17 +740,6 @@ Bounds Typer::Visitor::TypeFinish(Node* node) {
 }
 
 
-Bounds Typer::Visitor::TypeDeadValue(Node* node) {
-  return Bounds(Type::None(zone()), Type::Any(zone()));
-}
-
-
-Bounds Typer::Visitor::TypeDeadEffect(Node* node) {
-  UNREACHABLE();
-  return Bounds();
-}
-
-
 Bounds Typer::Visitor::TypeFrameState(Node* node) {
   // TODO(rossberg): Ideally FrameState wouldn't have a value output.
   return Bounds(Type::None(zone()), Type::Internal(zone()));
@@ -780,6 +767,11 @@ Bounds Typer::Visitor::TypeProjection(Node* node) {
 }
 
 
+Bounds Typer::Visitor::TypeDead(Node* node) {
+  return Bounds::Unbounded(zone());
+}
+
+
 // JS comparison operators.