284933 – sys-libs/glibc-2.9_p20081201-r2: libm pow() function does not report floating point underflow exception

Bug 284933 - sys-libs/glibc-2.9_p20081201-r2: libm pow() function does not report floating point underflow exception

Summary: sys-libs/glibc-2.9_p20081201-r2: libm pow() function does not report floating...

Status:	RESOLVED UPSTREAM

Alias:	None

Product:	Gentoo Linux
Classification:	Unclassified
Component:	[OLD] Core system (show other bugs)
Hardware:	AMD64 Linux

Importance:	High normal (vote)
Assignee:	Gentoo Toolchain Maintainers

URL:	http://sourceware.org/bugzilla/show_b...
Whiteboard:
Keywords:

Depends on:
Blocks:

Reported:	2009-09-14 14:00 UTC by Samuel Tardieu
Modified:	2009-10-26 09:57 UTC (History)
CC List:	0 users

See Also:
Package list:
Runtime testing required:	---

Attachments
Test case (t.c,605 bytes, text/plain) 2009-09-14 14:00 UTC, Samuel Tardieu	Details
View All Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.

Description Samuel Tardieu 2009-09-14 14:00:11 UTC

[copied from https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/429113 -- a similar problem occurs in Gentoo]

The pow() function in the standard C library does not report a floating point underflow exception like it is supposed to.


Reproducible: Always

Steps to Reproduce:
1. Compile the attached program with '-O0 -fno-builtin-pow -lm'.
2. Then run it.

Actual Results:  
0.000000
exceptions:
 inexact

Expected Results:  
0.000000
exceptions:
 inexact
 underflow

Works fine on x86. The glibc team asks to report problems through affected distributions first and Gentoo has the bug (as does Ubuntu).

Comment 1 Samuel Tardieu 2009-09-14 14:00:52 UTC

Created attachment 204058 [details]
Test case

Comment 2 SpanKY gentoo-dev

2009-10-26 09:57:13 UTC

really no chance of us debugging & fixing this ourselves.  pushed upstream.