[turbofan] Handle impossible types (Type::None()) in the backend.

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 2154 matching lines @@
 }
 
 Type* Typer::Visitor::TypeFloat64SilenceNaN(Node* node) {
   return Type::UntaggedFloat64();
 }
 
 Type* Typer::Visitor::TypeChangeInt32ToInt64(Node* node) {
   return Type::Internal();
 }
 
-
 Type* Typer::Visitor::TypeChangeUint32ToFloat64(Node* node) {
   return Type::Intersect(Type::Unsigned32(), Type::UntaggedFloat64(), zone());
 }
 
-
 Type* Typer::Visitor::TypeChangeUint32ToUint64(Node* node) {
   return Type::Internal();
 }
 
+Type* Typer::Visitor::TypeImpossibleToWord32(Node* node) {
+  return Type::None();
+}
+
+Type* Typer::Visitor::TypeImpossibleToWord64(Node* node) {
+  return Type::None();
+}
+
+Type* Typer::Visitor::TypeImpossibleToFloat32(Node* node) {
+  return Type::None();
+}
+
+Type* Typer::Visitor::TypeImpossibleToFloat64(Node* node) {
+  return Type::None();
+}
+
+Type* Typer::Visitor::TypeImpossibleToTagged(Node* node) {
+  return Type::None();
+}
+
+Type* Typer::Visitor::TypeImpossibleToBit(Node* node) { return Type::None(); }
 
 Type* Typer::Visitor::TypeTruncateFloat64ToFloat32(Node* node) {
   return Type::Intersect(Type::Number(), Type::UntaggedFloat32(), zone());
 }
 
 Type* Typer::Visitor::TypeTruncateFloat64ToWord32(Node* node) {
   return Type::Intersect(Type::Integral32(), Type::UntaggedIntegral32(),
                          zone());
 }
 
-
 Type* Typer::Visitor::TypeTruncateInt64ToInt32(Node* node) {
   return Type::Intersect(Type::Signed32(), Type::UntaggedIntegral32(), zone());
 }
 
 Type* Typer::Visitor::TypeRoundFloat64ToInt32(Node* node) {
   return Type::Intersect(Type::Signed32(), Type::UntaggedIntegral32(), zone());
 }
 
 Type* Typer::Visitor::TypeRoundInt32ToFloat32(Node* node) {
   return Type::Intersect(Type::PlainNumber(), Type::UntaggedFloat32(), zone());
@@ skipping 323 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