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From: "vogt at linux dot vnet.ibm.com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug go/63269] libgo/math test failures in TestLog2 Date: Wed, 05 Nov 2014 14:34:00 -0000 [thread overview] Message-ID: <bug-63269-4-ii2F9ze6ev@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-63269-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63269 --- Comment #4 from Dominik Vogt <vogt at linux dot vnet.ibm.com> --- regarding 2) > I'm not entirely persuaded by your argument for item 2. ... Hm, good that you doubted it, because the actual mistake is somehwere else: The unpatched code has if l != float64(i) but if you want to use a tolerance here this must become if !veryclose(float64(i), l) { With the argument reversed. This could/should be cleaned up by renaming the arguments of the tolerance() function, e.g. a -> expected, b -> result, e -> maxerr. > Zero is a special > value. When we expect a zero, we should get a zero, not something close to > zero. I don't think this change is correct in general. It may be correct for > some specific cases, but then we need to investigate those. Actually, this has nothing to do with 0 being special here, abut with scaling of the allowed error: Multiplying it by 0 yields zero error tolerance, so the tolerance() function does not do that. --> This chunk is not necessary, but a (separate) cleanup patch might help to avoid future confusion.
next prev parent reply other threads:[~2014-11-05 14:34 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-09-15 14:10 [Bug go/63269] New: " vogt at linux dot vnet.ibm.com 2014-09-15 14:12 ` [Bug go/63269] " vogt at linux dot vnet.ibm.com 2014-09-17 8:35 ` vogt at linux dot vnet.ibm.com 2014-11-05 3:54 ` ian at airs dot com 2014-11-05 14:34 ` vogt at linux dot vnet.ibm.com [this message] 2014-11-05 16:47 ` vogt at linux dot vnet.ibm.com 2014-11-06 10:18 ` vogt at linux dot vnet.ibm.com
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