Revert r9612, it hits an assertion under special circumstances.

Problematic code is e.g.:

   function typeofViaVariable() {
     var foo = typeof({})
     return foo === "undefined";
   }
Review URL: http://codereview.chromium.org/8283036

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9640 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen.cc

@@ -5789,65 +5789,35 @@ Representation HGraphBuilder::ToRepresentation(TypeInfo info) {
 
 
 void HGraphBuilder::HandleLiteralCompareTypeof(CompareOperation* expr,
-                                               HTypeof* typeof_expr,
+                                               Expression* sub_expr,
                                                Handle<String> check) {
-  HValue* value = typeof_expr->value();
+  CHECK_ALIVE(VisitForTypeOf(sub_expr));
+  HValue* value = Pop();
   HTypeofIsAndBranch* instr = new(zone()) HTypeofIsAndBranch(value, check);
   instr->set_position(expr->position());
-  ast_context()->ReturnControl(instr, expr->id());
-  typeof_expr->DeleteAndReplaceWith(NULL);
+  return ast_context()->ReturnControl(instr, expr->id());
 }
 
 
-static bool MatchLiteralCompareNil(HValue* left,
-                                   Token::Value op,
-                                   HValue* right,
-                                   Handle<Object> nil,
-                                   HValue** expr) {
-  if (left->IsConstant() &&
-      HConstant::cast(left)->handle().is_identical_to(nil) &&
-      Token::IsEqualityOp(op)) {
-    *expr = right;
+bool HGraphBuilder::TryLiteralCompare(CompareOperation* expr) {
+  Expression *sub_expr;
+  Handle<String> check;
+  if (expr->IsLiteralCompareTypeof(&sub_expr, &check)) {
+    HandleLiteralCompareTypeof(expr, sub_expr, check);
     return true;
   }
-  return false;
-}
-
 
-static bool MatchLiteralCompareTypeof(HValue* left,
-                                      Token::Value op,
-                                      HValue* right,
-                                      HTypeof** typeof_expr,
-                                      Handle<String>* check) {
-  if (left->IsTypeof() &&
-      Token::IsEqualityOp(op) &&
-      right->IsConstant() &&
-      HConstant::cast(right)->HasStringValue()) {
-    *typeof_expr = HTypeof::cast(left);
-    *check = Handle<String>::cast(HConstant::cast(right)->handle());
+  if (expr->IsLiteralCompareUndefined(&sub_expr)) {
+    HandleLiteralCompareNil(expr, sub_expr, kUndefinedValue);
     return true;
   }
-  return false;
-}
-
-
-static bool IsLiteralCompareTypeof(HValue* left,
-                                   Token::Value op,
-                                   HValue* right,
-                                   HTypeof** typeof_expr,
-                                   Handle<String>* check) {
-  return MatchLiteralCompareTypeof(left, op, right, typeof_expr, check) ||
-      MatchLiteralCompareTypeof(right, op, left, typeof_expr, check);
-}
 
+  if (expr->IsLiteralCompareNull(&sub_expr)) {
+    HandleLiteralCompareNil(expr, sub_expr, kNullValue);
+    return true;
+  }
 
-static bool IsLiteralCompareNil(HValue* left,
-                                Token::Value op,
-                                HValue* right,
-                                Handle<Object> nil,
-                                HValue** expr) {
-  return MatchLiteralCompareNil(left, op, right, nil, expr) ||
-      MatchLiteralCompareNil(right, op, left, nil, expr);
+  return false;
 }
 
 
@@ -5868,9 +5838,11 @@ void HGraphBuilder::VisitCompareOperation(CompareOperation* expr) {
     return ast_context()->ReturnControl(instr, expr->id());
   }
 
+  // Check for special cases that compare against literals.
+  if (TryLiteralCompare(expr)) return;
+
   TypeInfo type_info = oracle()->CompareType(expr);
   // Check if this expression was ever executed according to type feedback.
-  // Note that for the special typeof/null/undefined cases we get unknown here.
   if (type_info.IsUninitialized()) {
     AddInstruction(new(zone()) HSoftDeoptimize);
     current_block()->MarkAsDeoptimizing();
@@ -5885,20 +5857,6 @@ void HGraphBuilder::VisitCompareOperation(CompareOperation* expr) {
   HValue* left = Pop();
   Token::Value op = expr->op();
 
-  HTypeof* typeof_expr = NULL;
-  Handle<String> check;
-  if (IsLiteralCompareTypeof(left, op, right, &typeof_expr, &check)) {
-    return HandleLiteralCompareTypeof(expr, typeof_expr, check);
-  }
-  HValue* sub_expr = NULL;
-  Factory* f = graph()->isolate()->factory();
-  if (IsLiteralCompareNil(left, op, right, f->undefined_value(), &sub_expr)) {
-    return HandleLiteralCompareNil(expr, sub_expr, kUndefinedValue);
-  }
-  if (IsLiteralCompareNil(left, op, right, f->null_value(), &sub_expr)) {
-    return HandleLiteralCompareNil(expr, sub_expr, kNullValue);
-  }
-
   if (op == Token::INSTANCEOF) {
     // Check to see if the rhs of the instanceof is a global function not
     // residing in new space. If it is we assume that the function will stay the
@@ -5987,11 +5945,13 @@ void HGraphBuilder::VisitCompareOperation(CompareOperation* expr) {
 
 
 void HGraphBuilder::HandleLiteralCompareNil(CompareOperation* expr,
-                                            HValue* value,
+                                            Expression* sub_expr,
                                             NilValue nil) {
   ASSERT(!HasStackOverflow());
   ASSERT(current_block() != NULL);
   ASSERT(current_block()->HasPredecessor());
+  CHECK_ALIVE(VisitForValue(sub_expr));
+  HValue* value = Pop();
   EqualityKind kind =
       expr->op() == Token::EQ_STRICT ? kStrictEquality : kNonStrictEquality;
   HIsNilAndBranch* instr = new(zone()) HIsNilAndBranch(value, kind, nil);

src/hydrogen.h

@@ -912,11 +912,12 @@ class HGraphBuilder: public AstVisitor {
                                   HValue* receiver,
                                   SmallMapList* types,
                                   Handle<String> name);
+  bool TryLiteralCompare(CompareOperation* expr);
   void HandleLiteralCompareTypeof(CompareOperation* expr,
-                                  HTypeof* typeof_expr,
+                                  Expression* sub_expr,
                                   Handle<String> check);
   void HandleLiteralCompareNil(CompareOperation* expr,
-                               HValue* value,
+                               Expression* sub_expr,
                                NilValue nil);
 
   HStringCharCodeAt* BuildStringCharCodeAt(HValue* context,