Bug 1313447

Summary:	Test suite failure: math/test-float, math/test-float-finite and math/test-ifloat
Product:	[Fedora] Fedora	Reporter:	Carlos O'Donell <codonell>
Component:	glibc	Assignee:	glibc team <glibc-bugzilla>
Status:	CLOSED EOL	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	26	CC:	arjun.is, codonell, dj, extras-qa, fweimer, jakub, law, mfabian, pfrankli, siddhesh
Target Milestone:	---
Target Release:	---
Hardware:	i686
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:	1313443	Environment:
Last Closed:	2018-05-29 11:23:51 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1313443
Bug Blocks:

Description Carlos O'Donell 2016-03-01 15:40:46 UTC

+++ This bug was initially created as a clone of Bug #1313443 +++

On i686 the math/test-float, math/test-float-finite and math/test-ifloat all fail because j0 is off by an ULP. A single ULP difference might be due to a number of factors, but is otherwise OK for a function like this. The upstream ULPs might need to be adjusted and then backported. Otherwise it's a mistake somewhere in the bessel function support that we lost 1 ULP of precision.

Upstream discussion:
https://www.sourceware.org/ml/libc-alpha/2016-03/msg00009.html

testing float (without inline functions)
Failure: Test: j0_downward (0xap+0)
Result:
 is:         -2.45935813e-01  -0x1.f7ad32p-3
 should be:  -2.45935768e-01  -0x1.f7ad2cp-3
 difference:  4.47034835e-08   0x1.800000p-25
 ulp       :  3.0000
 max.ulp   :  2.0000
Maximal error of `j0_downward'
 is      : 3 ulp
 accepted: 2 ulp
Test suite completed:
  58942 test cases plus 53146 tests for exception flags and
    53146 tests for errno executed.
  2 errors occurred.

testing float (finite-math-only)
Failure: Test: j0_downward (0xap+0)
Result:
 is:         -2.45935813e-01  -0x1.f7ad32p-3
 should be:  -2.45935768e-01  -0x1.f7ad2cp-3
 difference:  4.47034835e-08   0x1.800000p-25
 ulp       :  3.0000
 max.ulp   :  2.0000
Maximal error of `j0_downward'
 is      : 3 ulp
 accepted: 2 ulp
Test suite completed:
  46382 test cases plus 41098 tests for exception flags and
    0 tests for errno executed.
  2 errors occurred.

testing float (inline functions)
Failure: Test: j0_downward (0xap+0)
Result:
 is:         -2.45935813e-01  -0x1.f7ad32p-3
 should be:  -2.45935768e-01  -0x1.f7ad2cp-3
 difference:  4.47034835e-08   0x1.800000p-25
 ulp       :  3.0000
 max.ulp   :  2.0000
Maximal error of `j0_downward'
 is      : 3 ulp
 accepted: 2 ulp
Test suite completed:
  58518 test cases plus 0 tests for exception flags and
    0 tests for errno executed.
  2 errors occurred.

--- Additional comment from Carlos O'Donell on 2016-03-01 10:40:06 EST ---

It might also be a change introduced by gcc 6 which results in the loss of one ULP (as suggested in my upstream post).

Comment 1 Carlos O'Donell 2016-03-01 15:41:08 UTC

Also seen in Rawhide.

Comment 2 Jan Kurik 2016-07-26 04:09:33 UTC

This bug appears to have been reported against 'rawhide' during the Fedora 25 development cycle.
Changing version to '25'.

Comment 3 Fedora End Of Life 2017-02-28 09:55:20 UTC

This bug appears to have been reported against 'rawhide' during the Fedora 26 development cycle.
Changing version to '26'.

Comment 4 Fedora End Of Life 2018-05-03 08:49:11 UTC

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Comment 5 Fedora End Of Life 2018-05-29 11:23:51 UTC

Fedora 26 changed to end-of-life (EOL) status on 2018-05-29. Fedora 26
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