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

[Christian Thalinger]

Looks good.  -- Chris

On Jul 13, 2012, at 12:46 PM, Vladimir Kozlov wrote:

> I updated webrev. I removed uncast() changes from this fix, we do it later. Tested with compiler and java/jang regression tests.
> 
> http://cr.openjdk.java.net/~kvn/7123926/webrev.01
> 
> Thanks,
> Vladimir
> 
> Vladimir Kozlov wrote:
>> I looked again on my changes and, I think, the lines with push_int();continue; should be also under (arg->outcnt() == 1) condition. If we don't remove call to Integer.toString() - use its result. Otherwise we have to generate conversion from int to String by hand for each use (see int_getChars()). As result Integer.toString() code will not be folded by later optimizations for the case I showed in previous mail. I need to do more testing for this and will resend webrev later.
>> > I'm a little bit worried about this part after seeing your fix for 7181658. Do you think it's safe to use uncast()
>> It was another Vladimir (Ivanov) who fixed 7181658 :-)
>> > this way, or should we use eqv_uncast() for comparison at the use sites of StringConcat::argument_uncast()?
>> I think using uncast() in argument_uncast() is safe, it is used only in related code. The first time argument_uncast() is called to find a Proj node from SB.toString() call. Then that Proj node passed to merge() method as 'arg'. And in the merge() method argument_uncast() is called second time to compare with that passed 'arg'.
>> Thanks,
>> Vladimir
>> On 7/5/12 8:23 PM, Krystal Mok wrote:
>>> Comments inline:
>>> 
>>> On Fri, Jul 6, 2012 at 10:38 AM, Vladimir Kozlov <vladimir.kozlov at oracle.com <mailto: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 at oracle.com>
>>>        <mailto:vladimir.kozlov at __oracle.com <mailto: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
>>> 
>>> 
>>>