[Trivial] Exclude 1 math test on DFly.

[dkgroot]

Not 100% what is causing this check to fail / or what this test is trying to prove):
assert(pow(-1.0L, 1/real.epsilon - 1.0L) == -1.0L);

Running (In D + ldc):

printf("%f\n", pow(-1.0L, 1/real.epsilon));
printf("%f\n", pow(-1.0L, 1/real.epsilon - 1.0L));

gives:

0.000000
nan

However (C + gcc -lm):

printf("%f\n", pow(-1.0L, 1/FLT_EPSILON));
printf("%f\n", pow(-1.0L, 1/FLT_EPSILON - 1.0L));

gives:

1.000000
-1.000000

Which is the correct answer.

Excluding the test on dragonfly for now, until i figure out the cause.

[dkgroot]

DFly SemaphoreCI

[JohanEngelen]

I think it's better to spend more time figuring out what is causing the problem first.
Do you have an ideas about what could be the cause? (what's the real size of DFly? Is a stdlib call done for pow? If so, is the DFly stdlib doing something different from other platforms?)

[dkgroot]

@JohanEngelen
i am not 100% sure about all of this:

• pow() is mapped to /usr/include/math.h (ie: libm ) (at least i hope so / how can i verify this ?).
• druntime:/src/core/stdc/config.d -> alias real c_long_double; ()

[kinke]

how can i verify this ?

Launch a debugger and step into it. You'll probably want to link against the debug runtime for debug infos in Phobos: -g -link-debuglib. Be sure to have a thorough look at the exponent arg (1/real.epsilon).

[kinke]

Well at least in current ltsmaster, the libm function is definitely not called, it's all implemented in D: https://github.com/ldc-developers/phobos/blob/ldc-ltsmaster/std/math.d#L6884

[dkgroot]

Will have another stab at it tomorrow.
BTW: I only excluded the test, to get my CI to be able to compile all the rest (as a check).

[redstar]

I check this, too, because I think I introduced this failure with #56.

[dkgroot]

@redstar thanks for the update / reference !
Will check tomorrow with / without #56 to see if that resolves the issue (Meaning this PR could be dropped!

[redstar]

#60 fixes the problem for me.

[redstar]

Indeed, the unit test failure in std.math is fixed now on Travis. Please check your build with the latest update.

[dkgroot]

@redstar Thanks for the update. Closing this PR