Remove invalid HCheckValue case in check elimination.

Also eliminate a useless copy of the map set in case of
HCheckMaps.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/256593011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@21033 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen-check-elimination.cc

@@ -72,10 +72,6 @@ class HCheckTable : public ZoneObject {
         ReduceCheckMaps(HCheckMaps::cast(instr));
         break;
       }
-      case HValue::kCheckValue: {
-        ReduceCheckValue(HCheckValue::cast(instr));
-        break;
-      }
       case HValue::kLoadNamedField: {
         ReduceLoadNamedField(HLoadNamedField::cast(instr));
         break;
@@ -305,7 +301,7 @@ class HCheckTable : public ZoneObject {
     if (entry != NULL) {
       // entry found;
       MapSet a = entry->maps_;
-      MapSet i = instr->map_set()->Copy(phase_->zone());
+      const UniqueSet<Map>* i = instr->map_set();
       if (a->IsSubset(i)) {
         // The first check is more strict; the second is redundant.
         if (entry->check_ != NULL) {
@@ -368,18 +364,6 @@ class HCheckTable : public ZoneObject {
     }
   }
 
-  void ReduceCheckValue(HCheckValue* instr) {
-    // Canonicalize HCheckValues; they might have their values load-eliminated.
-    HValue* value = instr->Canonicalize();
-    if (value == NULL) {
-      instr->DeleteAndReplaceWith(instr->value());
-      INC_STAT(removed_);
-    } else if (value != instr) {
-      instr->DeleteAndReplaceWith(value);
-      INC_STAT(redundant_);
-    }
-  }
-
   void ReduceLoadNamedField(HLoadNamedField* instr) {
     // Reduce a load of the map field when it is known to be a constant.
     if (!IsMapAccess(instr->access())) {