RFR JDK-8159720 C2 failures should not prevent C1 from compiling a method

[dean.long at oracle.com]

On 6/16/16 11:55 AM, Christian Thalinger wrote:

>
>> On Jun 16, 2016, at 10:51 AM, Carsten Varming <varming at gmail.com 
>> <mailto:varming at gmail.com>> wrote:
>>
>> Dear compiler list,
>>
>> I ran into a few methods that C2 failed to compile due to their 
>> number of arguments. To my surprise C2's failure caused the methods 
>> to be executed in the interpreter; although they had previously been 
>> compiled with C1. It turns out that a few C2 failures marks a method 
>> as not compilable on all tiers. I went through all possible failures 
>> with this behavior and I don't see reasons for preventing C1 from 
>> compiling a method after C2 failed. Perhaps some of you know the 
>> reasons behind this. I wrote a small patch to prevent C2 failures 
>> from marking a method as not compilable on all tiers when tiered 
>> compilation is on.
>
> I briefly looked at the history of that code and it’s there since the 
> initial load into Mercurial.  Does anyone have more history on this or 
> is this just an oversight from early-stage planning?
>
The _all_tiers part seems to come from 
https://bugs.openjdk.java.net/browse/JDK-4939496.

dl

>>
>> I filed a bug: JDK-8159720
>> and created a webrev: 
>> http://cr.openjdk.java.net/~cvarming/c2_failure_prevents_all_tiers/0/ 
>> <http://cr.openjdk.java.net/%7Ecvarming/c2_failure_prevents_all_tiers/0/>
>>
>> Carsten
>

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