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

[Roland Westrelin]

> Very good.
> 
> You need to use 2014 Copyright year in the test (no need for re-review).

Thanks, Vladimir.

What about you, Chris? Do you think it’s ok now?

Roland.

> 
> Thanks,
> Vladimir
> 
> On 1/17/14 2:19 AM, Roland Westrelin wrote:
>> What about this?
>> 
>> http://cr.openjdk.java.net/~roland/8027422/webrev.03/
>> 
>> Roland.
>> 
>> 
>> On Jan 16, 2014, at 10:11 AM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
>> 
>>> On 1/16/14 1:05 AM, Roland Westrelin wrote:
>>>> 
>>>> Thanks for reviewing this, Christian.
>>>> 
>>>>> Seeing all these:
>>>>> 
>>>>> true /* include_speculative */
>>>>> 
>>>>> I wonder if we should add new methods for these.  It would make it easier to see the users of the speculative versions.
>>>> 
>>>> A new meet_speculative() method?
>>>> I’m ok with it. Vladimir, what do you think?
>>> 
>>> I was going to suggest it too but then you need additional methods for other methods: join(), higher_equal(), filter(). So I am fine with it if you do all of them.
>>> 
>>> Vladimir
>>> 
>>>> 
>>>> Roland.
>>>> 
>>>>> 
>>>>> On Jan 14, 2014, at 7:25 AM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:
>>>>> 
>>>>>> 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.
>>>>>>>>>>>>>> 
>>>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>> 
>>>>>>> 
>>>>> 
>>>> 
>>