[turbofan] Proper dead code elimination as regular reducer.

src/compiler/typer.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/flags.h"
 #include "src/bootstrapper.h"
 #include "src/compiler/graph-reducer.h"
 #include "src/compiler/js-operator.h"
 #include "src/compiler/node.h"
 #include "src/compiler/node-properties.h"
@@ skipping 250 matching lines @@
       DECLARE_CASE(Switch)
       DECLARE_CASE(IfValue)
       DECLARE_CASE(IfDefault)
       DECLARE_CASE(Merge)
       DECLARE_CASE(Deoptimize)
       DECLARE_CASE(Return)
       DECLARE_CASE(TailCall)
       DECLARE_CASE(Terminate)
       DECLARE_CASE(OsrNormalEntry)
       DECLARE_CASE(OsrLoopEntry)
-      DECLARE_CASE(DeadControl)
       DECLARE_CASE(Throw)
       DECLARE_CASE(End)
 #undef DECLARE_CASE
       break;
     }
     return NoChange();
   }
 
   Bounds TypeNode(Node* node) {
     switch (node->opcode()) {
@@ skipping 24 matching lines @@
       DECLARE_CASE(Switch)
       DECLARE_CASE(IfValue)
       DECLARE_CASE(IfDefault)
       DECLARE_CASE(Merge)
       DECLARE_CASE(Deoptimize)
       DECLARE_CASE(Return)
       DECLARE_CASE(TailCall)
       DECLARE_CASE(Terminate)
       DECLARE_CASE(OsrNormalEntry)
       DECLARE_CASE(OsrLoopEntry)
-      DECLARE_CASE(DeadControl)
       DECLARE_CASE(Throw)
       DECLARE_CASE(End)
 #undef DECLARE_CASE
       break;
     }
     UNREACHABLE();
     return Bounds();
   }
 
   Type* TypeConstant(Handle<Object> value);
@@ skipping 408 matching lines @@
   UNREACHABLE();
   return Bounds();
 }
 
 
 Bounds Typer::Visitor::TypeFinish(Node* node) {
   return Operand(node, 0);
 }
 
 
-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()));
 }
 
 
 Bounds Typer::Visitor::TypeStateValues(Node* node) {
   return Bounds(Type::None(zone()), Type::Internal(zone()));
 }
 
 
 Bounds Typer::Visitor::TypeTypedStateValues(Node* node) {
   return Bounds(Type::None(zone()), Type::Internal(zone()));
 }
 
 
 Bounds Typer::Visitor::TypeCall(Node* node) {
   return Bounds::Unbounded(zone());
 }
 
 
 Bounds Typer::Visitor::TypeProjection(Node* node) {
   // TODO(titzer): use the output type of the input to determine the bounds.
   return Bounds::Unbounded(zone());
 }
 
 
+Bounds Typer::Visitor::TypeDead(Node* node) {
+  return Bounds::Unbounded(zone());
+}
+
+
 // JS comparison operators.
 
 
 Type* Typer::Visitor::JSEqualTyper(Type* lhs, Type* rhs, Typer* t) {
   if (lhs->Is(Type::NaN()) || rhs->Is(Type::NaN())) return t->singleton_false;
   if (lhs->Is(t->undefined_or_null) && rhs->Is(t->undefined_or_null)) {
     return t->singleton_true;
   }
   if (lhs->Is(Type::Number()) && rhs->Is(Type::Number()) &&
       (lhs->Max() < rhs->Min() || lhs->Min() > rhs->Max())) {
@@ skipping 1636 matching lines @@
       TYPED_ARRAYS(TYPED_ARRAY_CASE)
 #undef TYPED_ARRAY_CASE
     }
   }
   return Type::Constant(value, zone());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8