[PATCH] #pragma vectorize

[Chandler Carruth]

On Tue, Apr 22, 2014 at 12:47 PM, Hal Finkel <hfinkel at anl.gov> wrote:

> > I very much dislike the term 'interleave'. We had a great deal of
> > trouble with this term in the C++ committee. There are execution
> > models which want this information but do not guarantee
> > "interleaved" execution, and this is observable.
>
> In this particular case, I think this objection is misplaced. The
> particular transformation that we're discussing is, literally, one that
> provides interleaving of loop iterations. We could also call it unsequenced
> (as I mentioned in some earlier e-mail), but in some sense, this
> transformation is more specific than that.
>

I understand that. But I'm somewhat concerned *promising* it in the pragma.
It seems better to use a more generic term if there is a good one that
applies, and widen seems to.

> If this is just a cost model hint, I like "widen" quite a bit better,
> > and maybe there is a way to work "hint" or "cost" into the name?
>
> In some sense it is a cost model hint, but I'm not sure a user would see
> it as such.
>

Yea, I see that too.


>
> Using hint for the non-safety-asserting variants seems like a good idea.
> We should be clear with the users whether they are providing only a hint,
> or asserting something more.


Indeed. This is the key part.
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