[LLVMdev] [PATCH] parallel loop awareness to the LoopVectorizer

Hal Finkel hfinkel at anl.gov
Mon Jan 28 10:02:36 PST 2013

----- Original Message -----
> From: "Pekka Jääskeläinen" <pekka.jaaskelainen at tut.fi>
> To: "Hal Finkel" <hfinkel at anl.gov>
> Cc: "Nadav Rotem" <nrotem at apple.com>, "LLVM Developers Mailing List" <llvmdev at cs.uiuc.edu>
> Sent: Monday, January 28, 2013 11:58:09 AM
> Subject: Re: [LLVMdev] [PATCH] parallel loop awareness to the LoopVectorizer
> On 01/28/2013 07:36 PM, Pekka Jääskeläinen wrote:
> > If there's a "yes" from the analyzer it still prevents the
> > vectorization.
> > So, sort of a softened programmer-friendlier version of the
> > semantics.
> That said, I cannot think of a case where it would *harm* if the
> dependency analyzer, if it can actually prove a dependency,
> serializes
> the code.
> Thus, the same metadata can be used in both cases, if one doesn't
> care
> the possible wasted compilation time spent on the unnecessary
> dependency checking.

Agreed. In fact, it would not really be wasted because what we *should* do in that case it warn the user about it.


> --
> Pekka

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