Request for reviews (XS): 7123926: Some CTW test crash: !_control.contains(ctrl)

[Krystal Mok]

Comments inline:

On Fri, Jul 6, 2012 at 10:38 AM, Vladimir Kozlov <vladimir.kozlov at oracle.com
> wrote:

> Thank you, Kris
>
>
> Krystal Mok wrote:
>
>> Hi Vladimir,
>>
>> foo(Integer intobj) {
>>   String intstr = intobj.toString();
>>   String str = intstr + ", " + intstr;
>>
>> What should be the desired behavior for the case above?
>> Is it all right to skip all Integer.toString() calls, and let later
>> optimizations handle it?
>>
>
> You have only one toString() call. And it will be kept because it is
> referenced by debug info which is copied from SB constructor to new char[]
> constructor (AllocateArray node). It is needed for deoptimization since the
> bytecode will be executed after that call.
>
> I see. So that's what you meant in the original "Keep case". That makes
sense.


> The next code is the case when Integer.toString() will be eliminated by
> later optimizations:
>
>   StringBuilder sb = new StringBuilder();
>   String intstr = intobj.toString();
>   String str = sb.append(intstr).append(**intstr).toString();
>
> I also applied your uncast() suggestion in argument_uncast() method.
>
> I'm a little bit worried about this part after seeing your fix
for 7181658. Do you think it's safe to use uncast() this way, or should we
use eqv_uncast() for comparison at the use sites of
StringConcat::argument_uncast()?

Thanks,
Kris


> And I fixed typos.
>
> Thanks,
> Vladimir
>
>
>> And, two typos:
>>
>> 541               // chain. It's node could be eliminated only if it's
>> result
>>
>> It's -> Its. Other occurrences of "it's" should also be replaced with
>> "its".
>>
>> 543               // An other limitation: it should be used only once
>> because
>>
>> An other -> Another.
>>
>> - Kris
>>
>> On Fri, Jul 6, 2012 at 4:37 AM, Vladimir Kozlov <
>> vladimir.kozlov at oracle.com <mailto:vladimir.kozlov@**oracle.com<vladimir.kozlov at oracle.com>>>
>> wrote:
>>
>>     Vladimir Kozlov wrote:
>>
>>         http://cr.openjdk.java.net/~__**kvn/7123926/webrev<http://cr.openjdk.java.net/~__kvn/7123926/webrev>
>>
>>         <http://cr.openjdk.java.net/~**kvn/7123926/webrev<http://cr.openjdk.java.net/~kvn/7123926/webrev>
>> >
>>
>>         7123926: Some CTW test crash: !_control.contains(ctrl)
>>
>>         Don't try to eliminate Integer::toString() call node during
>>         String concatenation optimization if it's result has several uses.
>>
>>         Eliminate case:
>>           foo (Integer intob) {
>>             String str = "int: " + intobj;
>>
>>         Keep case:
>>           foo (Integer intob) {
>>             String intstr = intobj.toString();
>>             String str = "int: " + intobj; // second use is in SB
>>         allocation
>>
>>
>>     Sorry, it should be: "int: " + intstr;
>>
>>     Vladimir
>>
>>
>>         debug info
>>
>>         Tested with failed test.
>>
>>         Thanks,
>>         Vladimir
>>
>>
>>
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