RFR(M): 8027422: assert(_gvn.type(obj)->higher_equal(tjp)) failed: cast_up is no longer needed

[Vladimir Kozlov]

Looks good to me.

On 1/14/14 1:13 AM, Roland Westrelin wrote:
> http://cr.openjdk.java.net/~roland/8027422/webrev.02/
>
> I fixed the verification code at the end of Compile::remove_speculative_types(), used this format everywhere:
> t->filter(_type, true /* include_speculative */);
>
> renamed NodeHash::check_speculative_types() to NodeHash::check_no_speculative_types(), added PhaseIterGVN::check_no_speculative_types() and now call it from the verification code of Compile::remove_speculative_types().
>
> Do I need more than 1 review for this?

Yes, you need an other review for this change. Ask Chris or Igor.

Thanks,
Vladimir

>
> Roland.
>
>
> On Jan 13, 2014, at 11:03 AM, Roland Westrelin <roland.westrelin at oracle.com> wrote:
>
>>> compile.cpp: new verification code (under ASSERT) at the end of remove_speculative_types() checks only the root node - nothing else is pushed on worklist. Also add comment to this new code.
>>
>> Thanks for catching that.
>> Is:
>> // Verify that after the IGVN is over no speculative type has resurfaced
>> good as a comment?
>>
>>> Passing 'true' parameter is not very informative. You can use local variable:
>>>
>>> bool include_speculative = true;
>>> t->filter(_type, include_speculative);
>>>
>>> An other way to make code more informative is to add a comment to parameter:
>>>
>>> t->filter(_type, true /* include_speculative */);
>>>
>>> Either way is fine.
>>
>> Will do one of these.
>>
>> Thanks,
>> Roland.
>>
>>>
>>> Thanks,
>>> Vladimir
>>>
>>> On 1/10/14 1:46 AM, Roland Westrelin wrote:
>>>> Hi Vladimir,
>>>>
>>>> Here is a new webrev for this:
>>>> http://cr.openjdk.java.net/~roland/8027422/webrev.01/
>>>>
>>>> I fixed the issues you mentioned in your review.
>>>> I added a call to remove_speculative() to the ConNode constructor. When a node becomes constant, its speculative part can be not null. The IGVN doesn’t kill ConNodes so without a call to remove_speculative() a ConNode with a speculative part can sneak past the call to Compile::remove_speculative_types().
>>>> I also added a verification method:
>>>> NodeHash::check_speculative_types()
>>>> to check that no TypeNode with a speculative type is still in the IGVN hash table after Compile::remove_speculative_types()
>>>>
>>>> Roland.
>>>>
>>>> On Nov 19, 2013, at 8:49 PM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
>>>>
>>>>> On 11/19/13 11:45 AM, Roland Westrelin wrote:
>>>>>> Thanks for reviewing this, Vladimir.
>>>>>>
>>>>>> On Nov 19, 2013, at 1:34 AM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
>>>>>>
>>>>>>> Next 2 places in type.cpp pass 'true' to meet() unconditionally:
>>>>>>>
>>>>>>> 1929     return TypeAry::make(_elem->meet(a->_elem, true),
>>>>>>>
>>>>>>> 3812     const TypeAry *tary = _ary->meet(tap->_ary, true)->is_ary();
>>>>>>>
>>>>>>> Should TypeAryPtr::remove_speculative() also clean _speculative in element's type?
>>>>>>
>>>>>> You’re right. It probably should.
>>>>>> So I need to add a remove_speculative() method to TypeAry. Then the 2 places where true is passed to meet() for TypeAry don’t matter anymore because remove_speculative() is called from meet() and remove_speculative now has an effect on TypeAry, right?
>>>>>
>>>>> Right, passing 'true' will work in all cases then.
>>>>>
>>>>> Thanks,
>>>>> Vladimir
>>>>>
>>>>>>
>>>>>>> Could you make printing code with 'this_t' aligned again in Type::meet()?
>>>>>>
>>>>>> Sure.
>>>>>>
>>>>>> Roland.
>>>>>>
>>>>>>>
>>>>>>> thanks,
>>>>>>> Vladimir
>>>>>>>
>>>>>>> On 11/18/13 1:15 PM, Roland Westrelin wrote:
>>>>>>>> The root of the problem is that during the null check when the type of obj is improved in GraphKit::cast_not_null():
>>>>>>>> const Type *t_not_null = t->join(TypePtr::NOTNULL, true);
>>>>>>>> The join with TypePtr::NOTNULL is not applied to the speculative part. In fact, no meet between a TypeOopPtr and a TypePtr modifies the speculative part. One way to fix it would be to apply the meet with a TypePtr to the speculative part as well as the standard part of the type which I tried: then we need to move the _speculative field up in TypePtr and modify all operations on TypePtr to operate on _speculative so that the type system remains symmetric.
>>>>>>>> In many places where we mix a TypePtr with a TypeOopPtr we actually don’t care about the speculative part. I changed the following operations on Type:
>>>>>>>> higher_equal()
>>>>>>>> meet()
>>>>>>>> join()
>>>>>>>> filter()
>>>>>>>> so that by default they don’t return a result that include the speculative part of the type. Where we need the speculative part of the type, we have to explicitly request it.
>>>>>>>>
>>>>>>>> I also fixed a problem with Type nodes with a _type of TypeNarrowOop that wouldn’t drop the speculative part of the type during Compile::remove_speculative_types().
>>>>>>>> I included small clean ups that Mikael suggested privately (dropped the duplicate check for res->isa_oopptr() in TypeOopPtr::meet, make remove_speculative not go through the exercise of creating a new type if speculative is NULL).
>>>>>>>>
>>>>>>>> http://cr.openjdk.java.net/~roland/8027422/webrev.00/
>>>>>>>>
>>>>>>>> Roland.
>>>>>>>>
>>>>>>
>>>>
>>
>