[PR debug/41535] reset debug insns affected by scheduling

[H.J. Lu]

On Sat, Oct 17, 2009 at 10:21 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Fri, Oct 16, 2009 at 12:25 AM, Alexandre Oliva <aoliva@redhat.com> wrote:
>> On Oct 15, 2009, Alexandre Oliva <aoliva@redhat.com> wrote:
>>
>>> This patch enables nondebug insns to “depend” on debug insns, but these
>>> dependencies are handled in a special way: they don't stop the nondebug
>>> insn from being scheduled.  Rather, they enable the nondebug insn, once
>>> scheduled, to quickly reset debug insns that remain as unresolved
>>> dependencies.
>>
>>> To avoid using up more memory and complicating scheduler logic, I didn't
>>> add more dependency lists.
>>
>> Turns out when I was about to finish composing the e-mail above, this
>> idea occurred to me:
>>
>>> perhaps even discounting them in the list length counter.
>>
>> and it was pretty easy to implement and, surprise, it worked beautifully
>> and far more easily and more efficient than the earlier patch!
>>
>> Also, Jakub kindly tested the patch on other arches and found
>> -fmodulo-sched regressions: assertions failed that I'd put in there
>> precisely to prevent “debug deps”.  I'm yet to determine whether their
>> presence might cause -fcompare-debug differences; it didn't for the
>> testcases I tested, but they hardly exercised broad coverage.  I'll
>> start testing some optimized bootstrap-debugs and see if I run into any
>> such problems.  Fixing them will be for another patch, though.
>>
>> Here's the simplified patch I've regstrapped, so far, on
>> x86_64-linux-gnu.  Ok to install?
>>
>
> This may have caused:
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41739
>

This also caused:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44028


-- 
H.J.