Eliminate redundant smi checks

src/hydrogen.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4109 matching lines @@
   current_block()->Finish(compare_index);
 
   set_current_block(loop_successor);
   Drop(5);
 
   set_current_block(loop_body);
 
   HValue* key = AddInstruction(
       new(zone()) HLoadKeyedFastElement(
           environment()->ExpressionStackAt(2),  // Enum cache.
-          environment()->ExpressionStackAt(0),  // Iteration index.
-          OMIT_HOLE_CHECK));
+          environment()->ExpressionStackAt(0)));  // Iteration index.
 
   // Check if the expected map still matches that of the enumerable.
   // If not just deoptimize.
   AddInstruction(new(zone()) HCheckMapValue(
       environment()->ExpressionStackAt(4),
       environment()->ExpressionStackAt(3)));
 
   Bind(each_var, key);
 
   BreakAndContinueInfo break_info(stmt, 5);
@@ skipping 1333 matching lines @@
         return NULL;
     }
   }
   // It's an element load (!is_store).
   HoleCheckMode mode = IsFastPackedElementsKind(elements_kind) ?
       OMIT_HOLE_CHECK :
       PERFORM_HOLE_CHECK;
   if (IsFastDoubleElementsKind(elements_kind)) {
     return new(zone()) HLoadKeyedFastDoubleElement(elements, checked_key, mode);
   } else {  // Smi or Object elements.
-    return new(zone()) HLoadKeyedFastElement(elements, checked_key, mode);
+    return new(zone()) HLoadKeyedFastElement(elements, checked_key,
+                                             elements_kind);
   }
 }
 
 
 HInstruction* HGraphBuilder::BuildMonomorphicElementAccess(HValue* object,
                                                            HValue* key,
                                                            HValue* val,
                                                            HValue* dependency,
                                                            Handle<Map> map,
                                                            bool is_store) {
@@ skipping 27 matching lines @@
     HLoadExternalArrayPointer* external_elements =
         new(zone()) HLoadExternalArrayPointer(elements);
     AddInstruction(external_elements);
     return BuildExternalArrayElementAccess(external_elements, checked_key,
                                            val, map->elements_kind(), is_store);
   }
   ASSERT(fast_smi_only_elements ||
          fast_elements ||
          map->has_fast_double_elements());
   if (map->instance_type() == JS_ARRAY_TYPE) {
-    length = AddInstruction(new(zone()) HJSArrayLength(object, mapcheck));
+    length = AddInstruction(new(zone()) HJSArrayLength(object, mapcheck,
+                                                       HType::Smi()));
   } else {
     length = AddInstruction(new(zone()) HFixedArrayBaseLength(elements));
   }
   checked_key = AddInstruction(new(zone()) HBoundsCheck(key, length));
   return BuildFastElementAccess(elements, checked_key, val,
                                 map->elements_kind(), is_store);
 }
 
 
 HValue* HGraphBuilder::HandlePolymorphicElementAccess(HValue* object,
@@ skipping 134 matching lines @@
         HBasicBlock* if_jsarray = graph()->CreateBasicBlock();
         HBasicBlock* if_fastobject = graph()->CreateBasicBlock();
         HHasInstanceTypeAndBranch* typecheck =
             new(zone()) HHasInstanceTypeAndBranch(object, JS_ARRAY_TYPE);
         typecheck->SetSuccessorAt(0, if_jsarray);
         typecheck->SetSuccessorAt(1, if_fastobject);
         current_block()->Finish(typecheck);
 
         set_current_block(if_jsarray);
         HInstruction* length;
-        length = AddInstruction(new(zone()) HJSArrayLength(object, typecheck));
+        length = AddInstruction(new(zone()) HJSArrayLength(object, typecheck
+                                                           HType::Smi()));
         checked_key = AddInstruction(new(zone()) HBoundsCheck(key, length));
         access = AddInstruction(BuildFastElementAccess(
             elements, checked_key, val, elements_kind, is_store));
         if (!is_store) {
           Push(access);
         }
 
         *has_side_effects |= access->HasObservableSideEffects();
         if (position != -1) {
           access->set_position(position);
@@ skipping 179 matching lines @@
 
   CHECK_ALIVE(VisitForValue(expr->obj()));
 
   HInstruction* instr = NULL;
   if (expr->AsProperty()->IsArrayLength()) {
     HValue* array = Pop();
     AddInstruction(new(zone()) HCheckNonSmi(array));
     HInstruction* mapcheck =
         AddInstruction(HCheckInstanceType::NewIsJSArray(array, zone()));
     instr = new(zone()) HJSArrayLength(array, mapcheck);
-
   } else if (expr->IsStringLength()) {
     HValue* string = Pop();
     AddInstruction(new(zone()) HCheckNonSmi(string));
     AddInstruction(HCheckInstanceType::NewIsString(string, zone()));
     instr = new(zone()) HStringLength(string);
   } else if (expr->IsStringAccess()) {
     CHECK_ALIVE(VisitForValue(expr->key()));
     HValue* index = Pop();
     HValue* string = Pop();
     HValue* context = environment()->LookupContext();
@@ skipping 3271 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal