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* long double test failures due to underflow exception getting set?
@ 2017-07-19 21:34 Steve Ellcey
  2017-07-20  0:58 ` Carlos O'Donell
  0 siblings, 1 reply; 5+ messages in thread
From: Steve Ellcey @ 2017-07-19 21:34 UTC (permalink / raw)
  To: libc-alpha


Is anyone else seeing these failures with the latest glibc sources?
I am getting them on aarch64 (standard ToT sources) and was wondering
if this is an aarch64 specific problem or a more generic bug.  Since
all the failures involve long double I don't think they are using 
aarch64 specific code, but I could be wrong.

FAIL: math/test-ldouble-cexp
FAIL: math/test-ldouble-exp
FAIL: math/test-ldouble-finite-cexp
FAIL: math/test-ldouble-finite-exp

I think these failures are new and all of the failures listed are
about the Underflow exception being set:

I.e.

testing long double (without inline functions)
Failure: exp (-0x1p-10000): Exception "Underflow" set
Failure: exp (-0x2p-16384): Exception "Underflow" set
Failure: exp (-0x4p-16384): Exception "Underflow" set
Failure: exp (-0x4p-16448): Exception "Underflow" set
Failure: exp (-0x4p-16496): Exception "Underflow" set
Failure: exp (-0x8p-16448): Exception "Underflow" set


Steve Ellcey
sellcey@cavium.com

^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: long double test failures due to underflow exception getting set?
@ 2017-07-20 17:32 Wilco Dijkstra
  2017-07-20 17:40 ` Steve Ellcey
  0 siblings, 1 reply; 5+ messages in thread
From: Wilco Dijkstra @ 2017-07-20 17:32 UTC (permalink / raw)
  To: Ellcey, Steve, Carlos O'Donell; +Cc: libc-alpha, nd

Carlos wrote:
> Neither DJ nor Szabolcs's glibc 2.26 builds showed those failures:

Actually Szabolcs mentioned trunk GCC has some issues with long double.
I don't know the details but I imagine GCC lifts some FP operations across
fegetenv/fesetenv calls (or similar) which may be a bug depending on the
optimization setting (I guess you need -ftrapping-math to block such lifting).

Wilco

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2017-07-20 17:40 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-07-19 21:34 long double test failures due to underflow exception getting set? Steve Ellcey
2017-07-20  0:58 ` Carlos O'Donell
2017-07-20 16:28   ` Steve Ellcey
2017-07-20 17:32 Wilco Dijkstra
2017-07-20 17:40 ` Steve Ellcey

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