Bug 21423 – gcc 2.96 optimization bug

Bug 21423 - gcc 2.96 optimization bug

Summary:	gcc 2.96 optimization bug

Status:	CLOSED RAWHIDE

Aliases:	None

Product:	Red Hat Linux
Classification:	Retired
Component:	gcc (Show other bugs)
Sub Component:
Version:	7.0
Hardware:	i386 Linux

Priority	medium Severity medium
Target Milestone:	---
Target Release:	---
Assigned To:	Jakub Jelinek
QA Contact:	David Lawrence
Docs Contact:

URL:
Whiteboard:
Keywords:

Depends On:
Blocks:	21424
	Show dependency tree / graph

Reported:	2000-11-28 09:16 EST by Plummer, Martyn
Modified:	2007-04-18 12:30 EDT (History)
CC List:	0 users

See Also:
Fixed In Version:
Doc Type:	Bug Fix
Doc Text:
Story Points:	---
Clone Of:
Environment:
Last Closed:	2000-11-30 13:58:45 EST
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
Example program to show bug (1.42 KB, text/plain) 2000-11-28 09:17 EST, Plummer, Martyn	no flags	Details
Add an attachment (proposed patch, testcase, etc.)

External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHBA-2000:132	normal	SHIPPED_LIVE	Bug fixing update of GCC 2.96	2000-12-19 00:00:00 EST

Groups: None (edit)

Description Plummer, Martyn 2000-11-28 09:16:14 EST

This could be the same bug as #20580, but I am not really qualified to say,
so I'm submitting a separate report.

This bug came to light in the R language (see http://www.r-project.org and
R-base on Red Hat Powertools), causing the random number generator for the
Poisson distribution to misbehave.  The bug manifests itself only when the
code is optimized.

I am attaching a small example program - abstracted from the R source code
- that reproduces the bug.

When compiled with gcc -lm, the output is
9
10

When compiled with gcc -lm -O2, the output is
9
nan

If this works for you, a larger program is available that is much closer to
the original source.

Comment 1 Plummer, Martyn 2000-11-28 09:17:13 EST

Created attachment 5789 [details]
Example program to show bug

Comment 2 Jakub Jelinek 2000-11-28 11:39:07 EST

Actually, this is not related to #20580, but #21376 and seems to be fixed
by that patch as well. So if the patch gets accepted into CVS gcc, it will
be part of gcc-2.96-65 soon.

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