[PATCH] #pragma vectorize

[Alexander Musman]

>>>
>>> ParsePragma.cpp:1619: // Read '('
>>> This looks like a good place to use BalancedDelimiterTracker for
parsing '(' and ')’.

>>I don’t think it is needed. It isn’t used by any other #pragma directives
and the syntax here is rather simple. What do you think would be the
benefit?

This would improve consistency with the other places in clang where '(' and
')' are parsed. Otherwise it seems to be equivalent to handling '(' and ')'
manually.


>>> It would be very useful for auto-tuning libraries certainly. I am not
>>> sure how to support it currently. I suggest we leave it for a future
>>> commit.

>>I suspect that Alexey and Alexander can provide advice here.

For openmp clauses, we have methods in TreeTransform for this (e.g.
TransformOMPSafelenClause).
You will probably need something similar for attributes.



2014-04-29 4:19 GMT+04:00 Hal Finkel <hfinkel at anl.gov>:

> ----- Original Message -----
> > From: "Tyler Nowicki" <tnowicki at apple.com>
> > To: "Hal Finkel" <hfinkel at anl.gov>
> > Cc: "Alexey Bataev" <a.bataev at hotmail.com>, "llvm cfe" <
> cfe-commits at cs.uiuc.edu>, "Nadav Rotem" <nrotem at apple.com>,
> > "Alexander Musman" <alexander.musman at gmail.com>
> > Sent: Monday, April 28, 2014 7:09:13 PM
> > Subject: Re: [PATCH] #pragma vectorize
> >
> >
> > It would be very useful for auto-tuning libraries certainly. I am not
> > sure how to support it currently. I suggest we leave it for a future
> > commit.
>
> I suspect that Alexey and Alexander can provide advice here. I don't see
> how this is any different from the method used by the OpenMP pragrmas to
> support this... look at test/OpenMP/simd_ast_print.cpp and how the simdlen
> clause supports this.
>
> I think that part of the problem is that you're restricting the form of
> the value too early:
>
> The code:
>
> +    // Read the optimization value identifier.
>
> +    PP.Lex(Tok);
>
> +    if (Tok.isNot(tok::identifier) && Tok.isNot(tok::numeric_constant)) {
>
> +      PP.Diag(Tok.getLocation(), diag::err_expected) <<
>
> +      "enable, disable or integer value";
>
> +      return;
>
> +    }
>
> +
>
> +    Info->Value = Tok;
>
> and:
>
> +  if (Info->Value.is(tok::numeric_constant))
>
> +    Hint.ValueExpr = Actions.ActOnNumericConstant(Info->Value);
>
> looks wrong. We should parse arbitrary constant expressions here. The
> OpenMP code for simdlen, etc. does this, please emulate that.
>
> Thanks again!
>
>  -Hal
>
> >
> >
> > Thanks,
> >
> >
> > Tyler
> >
> >
> > On Apr 28, 2014, at 4:57 PM, Hal Finkel < hfinkel at anl.gov > wrote:
> >
> >
> >
> > ----- Original Message -----
> >
> >
> > From: "Tyler Nowicki" < tnowicki at apple.com >
> > To: "Alexander Musman" < alexander.musman at gmail.com >
> > Cc: "Alexey Bataev" < a.bataev at hotmail.com >, "llvm cfe" <
> > cfe-commits at cs.uiuc.edu >, "Nadav Rotem" < nrotem at apple.com >
> > Sent: Monday, April 28, 2014 6:53:40 PM
> > Subject: Re: [PATCH] #pragma vectorize
> >
> >
> >
> > Hi Alexander,
> >
> > Thanks for the review. I’ve updated the patch with your most of your
> > suggestions.
> >
> > Please review the updated patch.
> >
> >
> >
> > Do you plan to support substitution of integer template parameters
> > into pragma? Here is example:
> >
> >
> > cat ploop.cpp
> > template <int VLEN> void while_test(int *List, int Length) {
> > int i = 0;
> > #pragma loop vectorize(VLEN)
> > while(i < Length) {
> > List[i] = i*2;
> > i++;
> > }
> > }
> > int main() {
> > int L[100];
> > while_test<4> (L, 100);
> > return 0;
> > }
> >
> > I considered this, it is not currently supported. I’m not sure if it
> > makes sense. Lets leave this as a topic of future work for now.
> >
> > This kind of use case *must* be supported, it is very important for
> > libraries that auto-tune. Is there some reason that it is
> > complicated to support?
> >
> > -Hal
> >
> >
> >
> >
> >
> >
> >
> > ParsePragma.cpp:1619: // Read '('
> > This looks like a good place to use BalancedDelimiterTracker for
> > parsing '(' and ')’.
> >
> > I don’t think it is needed. It isn’t used by any other #pragma
> > directives and the syntax here is rather simple. What do you think
> > would be the benefit?
> >
> > Tyler
> >
> >
> >
> > _______________________________________________
> > cfe-commits mailing list
> > cfe-commits at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
> >
> >
> > --
> > Hal Finkel
> > Assistant Computational Scientist
> > Leadership Computing Facility
> > Argonne National Laboratory
> >
>
> --
> Hal Finkel
> Assistant Computational Scientist
> Leadership Computing Facility
> Argonne National Laboratory
>
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