RFR (XS): 7181658 CTW: assert(t->meet(t0) == t) failed: Not monotonic

[Vladimir Kozlov]

Looks good.

Thanks,
Vladimir

On 7/6/12 6:09 AM, Vladimir Ivanov wrote:
> Vladimir,
>
> Thanks for the review.
>
> Here's updated version:
> http://cr.openjdk.java.net/~vlivanov/7181658/webrev.01
>
> Best regards,
> Vladimir Ivanov
>
> On 7/6/12 2:40 AM, Vladimir Kozlov wrote:
>> Thank you, Vladimir, for taking and fixing this bug.
>>
>> Could you factor the condition into a separate function to be used in
>> both places?
>>
>> Thanks,
>> Vladimir
>>
>> Vladimir Ivanov wrote:
>>> http://cr.openjdk.java.net/~vlivanov/7181658/webrev.00
>>>
>>> 7181658 CTW: assert(t->meet(t0) == t) failed: Not monotonic
>>>
>>> One of node equivalence checks in CmpUNode::sub doesn't respect
>>> ConstraintCast nodes, which could lead to missed optimization
>>> opportunities. In this particular case it also breaks monotonicity
>>> assumption of CCP analysis due to a discrepancy in logic between 2 cases.
>>>
>>> I haven't been able to come up with a reduced regression test due to
>>> some tricky symbol resolution orderings which provoke the bug - even
>>> when the method bytecode is effectively the same! :-)
>>>
>>> Testing: failing test, CTW (full testlist)
>>>
>>> Best regards,
>>> Vladimir Ivanov
>>>
>