[PATCH] Fix PR 44691

[Andrey Belevantsev]

On 19.08.2010 19:53, H.J. Lu wrote:
> 2010/8/19 Andrey Belevantsev<abel@ispras.ru>:
>> On 19.08.2010 18:14, Andrey Belevantsev wrote:
>>>
>>> On 19.08.2010 18:12, H.J. Lu wrote:
>>>>
>>>> 2010/8/19 Andrey Belevantsev<abel@ispras.ru>:
>>>>>
>>>>> On 19.08.2010 17:28, H.J. Lu wrote:
>>>>>>
>>>>>> 2010/8/18 Andrey Belevantsev<abel@ispras.ru>:
>>>>>>>
>>>>>>> Hello,
>>>>>>>
>>>>>>> As explained in the audit trail, the problem was that in the selective
>>>>>>> scheduler I assumed that SUBREG_REG will always be a REG, which seems
>>>>>>> to
>>>>>>> be
>>>>>>> not the case. This is not quite in line with what documentation says,
>>>>>>> if
>>>>>>> I
>>>>>>> read it correctly, but it seems to be used in a number of backends, so
>>>>>>> the
>>>>>>> below patch just gives up substitution also when SUBREG_REG is not a
>>>>>>> register. Bootstrapped and tested on ia64, and verified that the test
>>>>>>> is
>>>>>>> fixed on x86_64.
>>>>>>>
>>>>>>> I think that this qualifies as obvious, so unless Vlad or other people
>>>>>>> have
>>>>>>> any comments, I'll commit it tomorrow.
>>>>>>>
>>>>>>> Yours, Andrey
>>>>>>>
>>>>>>> 2010-08-18 Andrey Belevantsev<abel@ispras.ru>
>>>>>>>
>>>>>>> PR rtl-optimization/44691
>>>>>>>
>>>>>>> * sel-sched.c (count_occurrences_1): Also punt when SUBREG_REG
>>>>>>> is not a register.
>>>>>>>
>>>>>>
>>>>>> Shouldn't we add the testcase?
>>>>>
>>>>> The test is fortran.dg/pr42294.f which is actually mentioned in the bug
>>>>> report. Sorry for not saying this explicitly in the mail.
>>>>>
>>>>
>>>> Normally this bug isn't trigged. You need to pass -O2
>>>> -fselective-scheduling2
>>>> to see it. You should copy gfortran.dg/pr42294.f and add -O2
>>>> -fselective-scheduling2.
>>>
>>> Ah, ok, I forgot about the explicit options. I will do that.
>>
>> Looking closely, pr42294.f happens to be another sel-sched bug, so it
>> already has "-O2 -fselective-scheduling2 -fsel-sched-pipelining
>> -funroll-all-loops" as dg-options.  So I guess this test should be enough,
>> what do you think?
>
> Why didn't it fail before? Does this bug fail only with "-O2
> -fselective-scheduling2"?
As mentioned in the PR, it started to fail with addition of the lea splits. 
  But you are right, you need to remove -funroll-loops from the compile 
options for the test to fail, so I have added a copy with just -O2 
-fselective-scheduling2 and committed as 163396.

Thanks for noticing,
Andrey