RFR(XS) 8046289: compiler/6340864/TestLongVect.java timeout with

[Tobias Hartmann]

Hi,

> Some background: Tobias and me have been looking at JDK-8014830 [1] 
> and JDK-8030976 fixed the problem. I suspect that this change will 
> return 8014830.

I just tested the changes and the bug (JDK-8014830) appears again. The 
problem is that no uncommon trap is added after the first loop and 
therefore the second loop, especially the call to inc(), is not 
profiled. The compiler assumes that the call site is never executed and 
does not inline inc().

I agree with Vladimir that we should not special case loop exits but 
find a solution for the case were we only have limited or no profile 
information.

Best,
Tobias

>
> Best regards,
> Vladimir Ivanov
>
> [1] https://bugs.openjdk.java.net/browse/JDK-8014830
>
> On 6/30/14 11:26 AM, Rickard Bäckman wrote:
>> Reviews please?
>>
>> Thanks
>> /R
>>
>> On 06/23, Rickard Bäckman wrote:
>>> Hi,
>>>
>>> a test started to timeout after JDK-8030976 was pushed. The test was 
>>> run
>>> with -Xcomp flag, so the profiling data available is non-existing or
>>> small. For some cases that meant that if a loop had at least 1 
>>> iteration
>>> executed it would look like the loop would always take the backedge and
>>> never end and we would generate an uncommon trap on the loop exit.
>>>
>>> The small change checks if the block we are considering turning into an
>>> uncommon trap is a loop exit.
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8046289
>>> Webrev: http://cr.openjdk.java.net/~rbackman/8046289/
>>>
>>> Thanks
>>> /R
>>
>>