src/hotspot/share/c1/c1_LIRGenerator.cpp

*** 1657,1672 ****
    __ shift_right(layout, Klass::_lh_array_tag_shift, layout);
    __ cmp(lir_cond_equal, layout, LIR_OprFact::intConst(Klass::_lh_array_tag_vt_value));
    __ branch(lir_cond_equal, T_ILLEGAL, slow_path);
  }
  
  void LIRGenerator::do_StoreIndexed(StoreIndexed* x) {
    assert(x->is_pinned(),"");
    bool is_loaded_flattened_array = x->array()->is_loaded_flattened_array();
    bool needs_range_check = x->compute_needs_range_check();
    bool use_length = x->length() != NULL;
!   bool obj_store = x->elt_type() == T_ARRAY || x->elt_type() == T_OBJECT;
    bool needs_store_check = obj_store && !is_loaded_flattened_array &&
                                          (x->value()->as_Constant() == NULL ||
                                           !get_jobject_constant(x->value())->is_null_object() ||
                                           x->should_profile());
  
--- 1657,1692 ----
    __ shift_right(layout, Klass::_lh_array_tag_shift, layout);
    __ cmp(lir_cond_equal, layout, LIR_OprFact::intConst(Klass::_lh_array_tag_vt_value));
    __ branch(lir_cond_equal, T_ILLEGAL, slow_path);
  }
  
+ bool LIRGenerator::needs_flattened_array_store_check(StoreIndexed* x) {
+   if (ValueArrayFlatten && x->elt_type() == T_OBJECT && x->array()->maybe_flattened_array()) {
+     ciType* type = x->value()->declared_type();
+     if (type != NULL && type->is_klass()) {
+       ciKlass* klass = type->as_klass();
+       if (klass->is_loaded() &&
+           !(klass->is_valuetype() && klass->as_value_klass()->flatten_array()) &&
+           !klass->is_java_lang_Object() &&
+           !klass->is_interface()) {
+         // This is known to be a non-flattenable object. If the array is flattened,
+         // it will be caught by the code generated by array_store_check().
+         return false;
+       }
+     }
+     // We're not 100% sure, so let's do the flattened_array_store_check.
+     return true;
+   }
+   return false;
+ }
+ 
  void LIRGenerator::do_StoreIndexed(StoreIndexed* x) {
    assert(x->is_pinned(),"");
    bool is_loaded_flattened_array = x->array()->is_loaded_flattened_array();
    bool needs_range_check = x->compute_needs_range_check();
    bool use_length = x->length() != NULL;
!   bool obj_store = x->elt_type() == T_OBJECT; assert(x->elt_type() != T_ARRAY, "never used");
    bool needs_store_check = obj_store && !is_loaded_flattened_array &&
                                          (x->value()->as_Constant() == NULL ||
                                           !get_jobject_constant(x->value())->is_null_object() ||
                                           x->should_profile());
  
*** 1682,1692 ****
      length.set_instruction(x->length());
      length.load_item();
    }
  
    if (needs_store_check || x->check_boolean()
!       || is_loaded_flattened_array || x->array()->maybe_flattened_array()) {
      value.load_item();
    } else {
      value.load_for_store(x->elt_type());
    }
  
--- 1702,1712 ----
      length.set_instruction(x->length());
      length.load_item();
    }
  
    if (needs_store_check || x->check_boolean()
!       || is_loaded_flattened_array || needs_flattened_array_store_check(x)) {
      value.load_item();
    } else {
      value.load_for_store(x->elt_type());
    }
  
*** 1727,1737 ****
      }
      access_flattened_array(false, array, index, value);
    } else {
      StoreFlattenedArrayStub* slow_path = NULL;
  
!     if (x->array()->maybe_flattened_array()) {
        // Check if we indeed have a flattened array
        index.load_item();
        slow_path = new StoreFlattenedArrayStub(array.result(), index.result(), value.result(), state_for(x));
        check_flattened_array(array, slow_path);
      }
--- 1747,1757 ----
      }
      access_flattened_array(false, array, index, value);
    } else {
      StoreFlattenedArrayStub* slow_path = NULL;
  
!     if (needs_flattened_array_store_check(x)) {
        // Check if we indeed have a flattened array
        index.load_item();
        slow_path = new StoreFlattenedArrayStub(array.result(), index.result(), value.result(), state_for(x));
        check_flattened_array(array, slow_path);
      }
*** 2044,2056 ****
      set_no_result(x);
    } else {
      LIR_Opr result = rlock_result(x, x->elt_type());
      LoadFlattenedArrayStub* slow_path = NULL;
  
!     if (x->array()->maybe_flattened_array()) {
        index.load_item();
!       // Check if we indeed have a flattened array
        slow_path = new LoadFlattenedArrayStub(array.result(), index.result(), result, state_for(x));
        check_flattened_array(array, slow_path);
      }
  
      DecoratorSet decorators = IN_HEAP | IS_ARRAY;
--- 2064,2076 ----
      set_no_result(x);
    } else {
      LIR_Opr result = rlock_result(x, x->elt_type());
      LoadFlattenedArrayStub* slow_path = NULL;
  
!     if (x->elt_type() == T_OBJECT && x->array()->maybe_flattened_array()) {
        index.load_item();
!       // if we are loading from flattened array, load it using a runtime call
        slow_path = new LoadFlattenedArrayStub(array.result(), index.result(), result, state_for(x));
        check_flattened_array(array, slow_path);
      }
  
      DecoratorSet decorators = IN_HEAP | IS_ARRAY;