Home
Reading
Searching
Subscribe
Sponsors
Statistics
Posting
Contact
Spam
Lists
Links
About
Hosting
Filtering
Features Download
Marketing
Archives
FAQ
Blog
 
Gmane
From: Hal Finkel <hfinkel <at> anl.gov>
Subject: [RFC] Removing BBVectorize?
Newsgroups: gmane.comp.compilers.llvm.devel
Date: Friday 28th November 2014 05:10:19 UTC (over 3 years ago)
Hi Everyone,

I propose that we remove BBVectorize from trunk. Here's why:

 - It never made it from "interesting experiment" to "production quality"
(it is not part of any in-tree optimization pipeline).

 - We now have an SLP vectorizer that we do use in production, had have for
some time.

 - BBVectorize otherwise needs refactoring, and the implementation has lots
of cutoffs (because the underlying algorithm is asymptotically expensive).

 - It has bugs (the way it tracks anti-dependencies from calls, for
example, is broken: PR20600).

In short, while BBVectorize was useful when it was added, it is unclear to
me whether or not its continuing presence outweighs the ongoing maintenance
costs and resulting user confusion (I still occasionally see users turning
it on when they likely would be happier with the SLP vectorizer instead).

So, if you're using it and would like it to stay, please speak up! Also,
BBVectorize has an API. Is anyone using it?

Thanks again (and happy Thanksgiving),
Hal

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory
 
CD: 3ms