[PATCH] D36258: Disable loop peeling during full unrolling pass.

[Teresa Johnson via llvm-commits]

On Thu, Sep 21, 2017 at 10:18 PM, Philip Reames via Phabricator <
reviews at reviews.llvm.org> wrote:

> reames added a comment.
>
> FYI, this patch causes a somewhat serious regression on one of our
> internal benchmarks.  Given we have a custom pass pipeline, it's definitely
> our responsibility to adapt to upstream changes not the other way around,
> but it would have helped us recognize the problem if either of two things
> had happened along with this patch:
>
> 1. The patch had been separated into two pieces: adding the new control
> know without changing the default and then a small patch changing the
> default.
> 2. The change had been announced in some way.  An email to llvm-dev
> probably would have been sufficient.
>
> Given we're hardly the only ones with custom pass pipelines, I'd encourage
> everyone involved (author, reviewers, etc..) to think about the upgrade
> path in similar cases which arise in the future.
>

Hi Phillip,

Sorry for the trouble. Will announce this type of change more widely in the
future. I didn't think to do that since it should occur later in the
pipeline, but I wasn't thinking about the case of a custom pipeline. It was
essentially a "bug" fix since it was an oversight to leave peeling enabled
during the full unrolling pass when it was added. Is your custom pass
pipeline not doing the later unrolling invocation?

Teresa


>
> Repository:
>   rL LLVM
>
> https://reviews.llvm.org/D36258
>
>
>
>


-- 
Teresa Johnson |  Software Engineer |  tejohnson at google.com |  408-460-2413
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20170922/944cf3f9/attachment.html>