[turbofan] Fix overly aggressive dead code elimination.

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/compiler/typer.h"
 
 #include "src/base/flags.h"
 #include "src/bootstrapper.h"
 #include "src/compilation-dependencies.h"
 #include "src/compiler/common-operator.h"
@@ skipping 792 matching lines @@
 Type* Typer::Visitor::TypeProjection(Node* node) {
   Type* const type = Operand(node, 0);
   if (type->Is(Type::None())) return Type::None();
   int const index = static_cast<int>(ProjectionIndexOf(node->op()));
   if (type->IsTuple() && index < type->AsTuple()->Arity()) {
     return type->AsTuple()->Element(index);
   }
   return Type::Any();
 }
 
-
-Type* Typer::Visitor::TypeDead(Node* node) { return Type::Any(); }
-
+Type* Typer::Visitor::TypeDead(Node* node) { return Type::None(); }
 
 // 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(Type::NullOrUndefined()) && rhs->Is(Type::NullOrUndefined())) {
     return t->singleton_true_;
   }
   if (lhs->Is(Type::Number()) && rhs->Is(Type::Number()) &&
@@ skipping 1780 matching lines @@
   }
   if (Type::IsInteger(*value)) {
     return Type::Range(value->Number(), value->Number(), zone());
   }
   return Type::Constant(value, zone());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8