Request for reviews (S): 7026700: regression in 6u24-rev-b23: Crash in C2 compiler in PhaseIdealLoop::build_loop_late_post
Vladimir Kozlov
vladimir.kozlov at oracle.com
Wed Apr 20 14:51:18 PDT 2011
Tom Rodriguez wrote:
> On Apr 20, 2011, at 12:11 PM, Vladimir Kozlov wrote:
>
>> This is fix for jdk7.
>>
>> http://cr.openjdk.java.net/~kvn/7026700/webrev
>>
>> Fixed 7026700: regression in 6u24-rev-b23: Crash in C2 compiler in PhaseIdealLoop::build_loop_late_post
>>
>> With EA memory slices should be created explicitly for non-static fields regardless the value of ReduceFieldZeroing flag.
>
> Do these really need to guarded? Couldn't we just always do it?
Yes, we can do it always. Which makes raw_mem_only parameter obsolete. Should I
remove it?
>
>> LoadNode::split_through_phi() should not check profitability since we want to eliminate loads from non-escaping allocations.
>
> What about this logic?
>
> // Skip the split if the region dominates some control edge of the address.
> if (cnt == 3 && !MemNode::all_controls_dominate(address, region))
> return NULL;
>
> Why should we give up when cnt == 3 and not others?
Yes, it is a bug, we should check all cases. I think my intention was to
restrict the call to expensive all_controls_dominate() only for loops. Fixed.
>
>> I also want to disable memory split verification code in EA until the fix for 6984348. It produces false negative results since the verification code does not cover all cases.
>
> Could you normal // comments or use #if 0 instead. It's should have a comment explaining why it's disabled too.
Done.
I updated webrev.
Thanks,
Vladimir
>
> tom
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