[cfe-dev] [test-suite] making polybench/symm succeed with "-Ofast" and "-ffp-contract=on"

[Sebastian Pop via cfe-dev]

On Thu, Oct 20, 2016 at 11:20 AM, Renato Golin <renato.golin at linaro.org> wrote:
> On 20 October 2016 at 16:15, Sebastian Pop <sebpop.llvm at gmail.com> wrote:
>> The test passes for a relative tolerance of 100,000.
>
> Right, we need to figure out how to reduce that. Probably some
> artifact of the reduction again...

To help understand what "relative tolerance" means, here is its
"semantics by example":
the error I get for gramschmidt compiled with relative tolerance 1e4 is:
A[31][44] = -0.017313 and B[31][44] = 0.000001 differ by 16187.949133
more than FP_ABSTOLERANCE = 0.000010, FP_TOLERANCE = 10000.000000