Request for reviews (S): 6809798: SafePointScalarObject node placed into incorrect block during GCM

[Vladimir Kozlov]

Thanks, Tom

I will replace comments.

Vladimir

Tom Rodriguez wrote:
> Ok.
> 
> Since you've split the processing into a new method would you remove the 
> copy of the comment about "Special control input processing" from the 
> original location?  Maybe a shorter comment like this:
> 
> // Fixup some control.  Constants without control get attached to root and
> // nodes that use is_block_proj() nodes should be attached to the region 
> that
> // starts their block.
> 
> Actually the existing comment for replace_block_proj_ctrl is pretty hard 
> to read.  How about:
> 
> // Nodes that have is_block_proj() nodes as their control need to use
> // the appropriate Region for their actual block as their control since
> // the projection will be in a predecessor block.
> 
> tom
> 
> On Feb 26, 2009, at 11:13 AM, Vladimir Kozlov wrote:
> 
>> I only saw asserts for SafePointScalarObjectNodes.
>> But patching control edge of pinned nodes before scheduling
>> affects all pinned nodes: safepoints, phis.
>> And I think this change is correct for all pinned nodes.
>>
>> I actually was not able to catch the case were
>> safepoint has block projection control to see what
>> happened. In the bugs case it was scheduled correctly
>> even with current code. But it could be the case
>> when control was set differently for SFPT and SPSO nodes
>> during IGVN in IfNode::dominated_by() which I fixed by
>> SafePointScalarObjectNode::depends_only_on_test() const { return false; }
>>
>> Thanks,
>> Vladimir
>>
>> Tom Rodriguez wrote:
>>> Were SafePointScalarObjectNodes the only one affected by this or will 
>>> this change the schedule of other nodes?
>>> tom
>>> On Feb 26, 2009, at 10:15 AM, Vladimir Kozlov wrote:
>>>> http://cr.openjdk.java.net/~kvn/6809798/webrev.00
>>>>
>>>> Fixed 6809798: SafePointScalarObject node placed into incorrect 
>>>> block during GCM
>>>>
>>>> Problem:
>>>> The main problem is that the control edge of a pinned node
>>>> could be replaced during schedule_early after the pinned
>>>> node scheduled into a block if the control node is a block
>>>> projection.
>>>> Also there were few places where the control edge of
>>>> a SafePointScalarObject node was not adjusted correctly.
>>>>
>>>> Solution:
>>>> Replace the control edge of a pinned node before scheduling.
>>>> Adjust the control edge of a SafePointScalarObject when needed.
>>>> Added few asserts to verify scheduling correctness for
>>>> pinned nodes and SafePointScalarObject node.
>>>>
>>>> Reviewed by:
>>>>
>>>> Fix verified (y/n): y
>>>>
>>>> Other testing:
>>>> JPRT, CTW (with -XX:+DoEscapeAnalysis)
>>>>
>