Bug 15406 - catan, catanh missing underflow exceptions
Summary: catan, catanh missing underflow exceptions
Status: RESOLVED FIXED
Alias: None
Product: glibc
Classification: Unclassified
Component: math (show other bugs)
Version: 2.17
: P2 normal
Target Milestone: ---
Assignee: Not yet assigned to anyone
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Blocks:
 
Reported: 2013-04-26 16:19 UTC by Joseph Myers
Modified: 2014-06-13 18:14 UTC (History)
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fweimer: security-

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Description Joseph Myers 2013-04-26 16:19:25 UTC 
catan and catanh can miss underflow exceptions in the case where the tiny result comes from the multiplication of a log by 0.25, and that multiplication is exact although the mathematical result of the log wasn't exact.  Examples on x86_64 are catan (0x1p511 + 0.5i) and catanh (0.5 + 0x1p511i).

(Before my recent fix for bug 15394, the tiny results would have been given inaccurately as 0, but still with missing underflow exception.)
Comment 1 Joseph Myers 2013-04-26 19:28:09 UTC 
Fixed for 2.18 by:

commit 9457fd952cafc701375fc9fae575a4aca1374de3
Author: Joseph Myers <joseph@codesourcery.com>
Date:   Fri Apr 26 19:26:22 2013 +0000

    Fix catan, catanh missing underflows (bug 15406).