[turbofan] Introduce DeadValue and DeadEffect operators.

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index f92de92013249e981d62a5deec48ca9786117f61..f960153be3c02a61efa0e8b44c9057d3a8cb55ef 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -253,7 +253,6 @@ class Typer::Visitor : public Reducer {
 #undef DECLARE_CASE
 
 #define DECLARE_CASE(x) case IrOpcode::k##x:
-      DECLARE_CASE(Dead)
       DECLARE_CASE(Loop)
       DECLARE_CASE(Branch)
       DECLARE_CASE(IfTrue)
@@ -269,6 +268,7 @@ 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
@@ -298,7 +298,6 @@ class Typer::Visitor : public Reducer {
 #undef DECLARE_CASE
 
 #define DECLARE_CASE(x) case IrOpcode::k##x:
-      DECLARE_CASE(Dead)
       DECLARE_CASE(Loop)
       DECLARE_CASE(Branch)
       DECLARE_CASE(IfTrue)
@@ -314,6 +313,7 @@ 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
@@ -742,6 +742,17 @@ 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()));