Bug 59826
| Summary: | library functions give floating point exceptions | ||||||||||
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| Product: | [Retired] Red Hat Linux | Reporter: | Robert M. Riches Jr. <rm.riches> | ||||||||
| Component: | glibc | Assignee: | Jakub Jelinek <jakub> | ||||||||
| Status: | CLOSED WONTFIX | QA Contact: | Brian Brock <bbrock> | ||||||||
| Severity: | medium | Docs Contact: | |||||||||
| Priority: | medium | ||||||||||
| Version: | 7.1 | CC: | fweimer | ||||||||
| Target Milestone: | --- | ||||||||||
| Target Release: | --- | ||||||||||
| Hardware: | alpha | ||||||||||
| OS: | Linux | ||||||||||
| Whiteboard: | |||||||||||
| Fixed In Version: | Doc Type: | Bug Fix | |||||||||
| Doc Text: | Story Points: | --- | |||||||||
| Clone Of: | Environment: | ||||||||||
| Last Closed: | 2002-02-13 18:15:42 UTC | Type: | --- | ||||||||
| Regression: | --- | Mount Type: | --- | ||||||||
| Documentation: | --- | CRM: | |||||||||
| Verified Versions: | Category: | --- | |||||||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||||||
| Embargoed: | |||||||||||
| Attachments: |
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Created attachment 45563 [details]
C program source
Created attachment 45565 [details]
compilation script that shows the problem
Created attachment 45566 [details]
compilation script that shows a workaround
There is just one libm and is not multilibbed, so you really cannot have both precise results for -mieee and flushing to zero for non-mieee at the same time. I'd suggest using -mieee always (e.g. the whole RHL alpha distribution is compiled that way), or before using return values from libm functions wrapping them in some function which flushes them to zero. |
Description of Problem: The default math libraries give floating point exceptions when doing fairly ordinary things, such as exp(-709.0) and then using the result. Version-Release number of selected component (if applicable): glibc-devel-2.2.4-19.3 How Reproducible: 100% Steps to Reproduce: 1. In a C program, do exp(-709.0) and then use the result. (Sample source code as an attachment.) 2. 3. Actual Results: Floating exception Expected Results: The result should be a usable FP number somewhere near or equal to zero. Additional Information: It appears the exp() function is returning a denormalized number, and later use of this number causes an exception. I had seen this issue and worked around it by using -mieee in the Rainbow information retrieval package, either the Festival speech synthesis package or the Phoenix speech recognition package, and xlock (-mode invert). However, on advice from experts on the axp-list mailing list, I now consider it a library bug.