llvm dev - Sep 2016 - [cfe-dev] a proposed script to help with test-suite programs that output _lots_ of FP numbers

On 29 September 2016 at 19:21, Sebastian Pop <sebpop.llvm at gmail.com>
wrote:
> Cumulating errors is a bad idea.
> As others have suggested, please prepare a patch that disables
> fp-contract on those testcases.
No, please, let's not disable things just because they fail.

If the test is not meaningful or if the results are not good, let's
just change the test in a meaningful way that can work with any FP
optimisation without changing meaning.

If it does change meaning, it's a bug and we *want* to catch.

cheers,
--renato

On Thu, Sep 29, 2016 at 2:05 PM, Renato Golin <renato.golin at linaro.org>
wrote:
> On 29 September 2016 at 19:21, Sebastian Pop <sebpop.llvm at
gmail.com> wrote:
>> Cumulating errors is a bad idea.
>> As others have suggested, please prepare a patch that disables
>> fp-contract on those testcases.
>
> No, please, let's not disable things just because they fail.
>
> If the test is not meaningful or if the results are not good, let's
> just change the test in a meaningful way that can work with any FP
> optimisation without changing meaning.
>
> If it does change meaning, it's a bug and we *want* to catch.
These tests are checking the results against a "golden file" output
computed with fp-contract=off.
IMHO the most sensible solution is to continue checking those tests
with the same flag
as at the time when the reference output has been recorded.

Thanks,
Sebastian

----- Original Message -----
> From: "Sebastian Pop via cfe-dev" <cfe-dev at
lists.llvm.org>
> To: "Renato Golin" <renato.golin at linaro.org>
> Cc: "llvm-dev" <llvm-dev at lists.llvm.org>,
"Sebastian Paul Pop" <s.pop at samsung.com>, "Abe
Skolnik"
> <a.skolnik at samsung.com>, "cfe-dev" <cfe-dev at
lists.llvm.org>
> Sent: Thursday, September 29, 2016 4:26:23 PM
> Subject: Re: [cfe-dev] [llvm-dev] a proposed script to help with test-suite
programs that output _lots_ of FP numbers
> 
> On Thu, Sep 29, 2016 at 2:05 PM, Renato Golin
> <renato.golin at linaro.org> wrote:
> > On 29 September 2016 at 19:21, Sebastian Pop
> > <sebpop.llvm at gmail.com> wrote:
> >> Cumulating errors is a bad idea.
> >> As others have suggested, please prepare a patch that disables
> >> fp-contract on those testcases.
> >
> > No, please, let's not disable things just because they fail.
> >
> > If the test is not meaningful or if the results are not good,
let's
> > just change the test in a meaningful way that can work with any FP
> > optimisation without changing meaning.
> >
> > If it does change meaning, it's a bug and we *want* to catch.
> 
> These tests are checking the results against a "golden file"
output
> computed with fp-contract=off.
> IMHO the most sensible solution is to continue checking those tests
> with the same flag
> as at the time when the reference output has been recorded.
We don't want to lose the more-stringent test coverage just because that no
longer might be the default mode. We'll also want, where practical, some
looser test mode that will work regardless of the FP contraction setting. Both
are important.

 -Hal
> 
> Thanks,
> Sebastian
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-- 
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory