[PATCH] Use AA in LoopVectorize

[Hal Finkel]

----- Original Message -----
> From: "Nadav Rotem" <nrotem at apple.com>
> To: hfinkel at anl.gov, aschwaighofer at apple.com, nrotem at apple.com
> Cc: llvm-commits at cs.uiuc.edu
> Sent: Sunday, July 20, 2014 9:51:36 PM
> Subject: Re: [PATCH] Use AA in LoopVectorize
> 
> Hi Hal,
> 
> Sorry for the delay in response.  The motivation for this change is
> clear and the direction makes sense. Quick question: did you measure
> the effect of this change on the mailing list? Were there any
> performance wins or losses?

You mean in the test suite? I saw nothing significant either way. 

Performance wise, things should be strictly better than before. I have a number of internal benchmarks that improved for two reasons:

 1. Loops accessing many different arrays, some of different types, now require fewer checks (and thus now vectorize when they didn't before).
 2. The loop being vectorized was an inner loop that, at runtime, had a relatively small trip count; the elimination of the unnecessary dependency checks was significant.

Thanks again,
Hal

> 
> Thanks,
> Nadav
> 
> http://reviews.llvm.org/D4599
> 
> 
> 

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory