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

Vladimir Ivanov vladimir.x.ivanov at oracle.com
Fri Jul 6 06:09:13 PDT 2012


Thanks for the review.

Here's updated version:

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

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