Re: Recent new atf test failures

[Paul Goyette <paul%whooppee.com@localhost>]

On Wed, 26 Mar 2014, David Laight wrote:

> On Wed, Mar 26, 2014 at 12:25:53PM -0700, Paul Goyette wrote:
> > Some time in the last two weeks, we've had a few new test cases failing
> > in my amd64 test-bed.
> >
> > Tests that used to pass, but currently failing
> >
> >         lib/csu/t_crt0/initfini3
> >         atf/atf-c/macros_test/detect_unused_tests
> >         atf/atf-c++/macros_test/detect_unused_tests
> >
> > Tests that currently fail, but don't seem to exist in older builds
> >
> >         lib/libm/t_exp/exp2_powers
> >         lib/libm/t_exp/exp2_values
>
> Those are some more extensive tests for exp2().
>
> The exp2_powers tests are failing to generate an 'overflow' result.
> They work for me on a real system - so it might be a qemu issue?
>
> Maybe qemu is using the x87 fpu (with 80 bit precision) to emulate
> the 64bit (and 32bit) SSE2 double (and float) maths - so the large
> mutiplies used to generate overflow fail.

Ah, OK.


> Actually, I wonder, have you rebuilt qemu since jeorg changed the
> default x87 precision to 80bits?
> That might be the difference between your tests and gson's tests
> (which only show some minor errors for exp2f(7.7) and exp2f(8.8).

No, I have not updated my qemu recently (several months).


> The exp2_values tests is showing up something odd in FP maths.
> I've not changes the exp2f() code, but I'm seeing different
> errors in my own testing (native on amd64) from earlier tests.
> However it might just be that the allowed error is too small.

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