Request for reviews (S): 7026700: regression in 6u24-rev-b23: Crash in C2 compiler in PhaseIdealLoop::build_loop_late_post

[Vladimir Kozlov]

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