Re: debug insns in SMS

[Alexandre Oliva <aoliva@redhat.com>]

Apologies for the duplicate ping, this one is now properly addressed to
the pass maintainer.

On Apr  9, 2012, Alexandre Oliva <aoliva@redhat.com> wrote:

> On May  4, 2011, Revital1 Eres <ERES@il.ibm.com> wrote:
>> Hello Alexandre
>>> I think this will restore proper functioning to SMS in the presence of
>>> debug insns.  A while ago, we'd never generate deps of non-debug insns
>>> on debug insns.  I introduced them to enable sched to adjust (reset)
>>> debug insns when non-debug insns were moved before them.  I believe it
>>> is safe to leave them out of the SCCs.  Even though this will end up
>>> causing some loss of debug info, that's probably unavoidable, and the
>>> end result after this change is pobably the best we can hope for.  Your
>>> thoughts?

>> Thanks for the patch!

>> I actually discussed this issue with Ayal yesterday.
>> Ayal also suggested to reconsider the edges that are created in
>> the DDG between real instructions and debug_insns. Currently, we create
>> bidirectional anti deps edges between them. This leads to the problem you
>> were trying to solve in the current patch (described below) where these
>> extra edges influence the construction of the strongly connected component
>> and the code generated with and w\o -g. Your patch seems to solve this
>> problem.
>> However I can not approve it as I'm not the maintainer (Ayal is).

> Ping?

> (Retested on x86_64-linux-gnu and i686-pc-linux-gnu)


> for  gcc/ChangeLog
> from  Alexandre Oliva  <aoliva@redhat.com>

> 	* ddg.c (build_intra_loop_deps): Discard deps of nondebug on debug.

Ping?  http://gcc.gnu.org/ml/gcc-patches/2012-04/msg00419.html

-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist      Red Hat Brazil Compiler Engineer