From: Joseph Myers <joseph@codesourcery.com>
To: Szabolcs Nagy <szabolcs.nagy@arm.com>
Cc: Patrick McGehearty <patrick.mcgehearty@oracle.com>,
<libc-alpha@sourceware.org>, <nd@arm.com>
Subject: Re: [PATCH] v11 Improves __ieee754_exp() performance by greater than 5x on sparc/x86.
Date: Fri, 2 Feb 2018 15:33:25 +0000 [thread overview]
Message-ID: <alpine.DEB.2.20.1802021530130.17793@digraph.polyomino.org.uk> (raw)
In-Reply-To: <361bac88-5538-227f-b6dc-76416178192c@arm.com>
On Fri, 2 Feb 2018, Szabolcs Nagy wrote:
> (i also removed the rounding mode settings in both cases
> as that can be avoided at least on aarch64)
There is or was certainly code in the existing exp that gives completely
wrong results in non-default rounding modes (that was bug 3976) - e.g.
using precision-extension techniques that require round-to-nearest -
though I don't know if that applies to the fast case code or if it's only
in code for slow cases (or code for slow cases but using other rounding
modes results in the slow cases getting used much more).
--
Joseph S. Myers
joseph@codesourcery.com
next prev parent reply other threads:[~2018-02-02 15:31 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-29 21:44 [PATCH] v11 Improves __ieee754_exp() performance by greater than 5x on sparc/x86 Patrick McGehearty
2018-02-02 14:40 ` Szabolcs Nagy
2018-02-02 15:33 ` Joseph Myers [this message]
2018-02-02 16:35 ` Szabolcs Nagy
2018-02-07 19:19 ` Patrick McGehearty
-- strict thread matches above, loose matches on Subject: below --
2018-02-08 11:40 Wilco Dijkstra
2018-02-14 1:18 ` Patrick McGehearty
2018-02-14 16:41 ` Joseph Myers
2018-02-14 20:05 ` Szabolcs Nagy
2018-02-22 19:22 ` Szabolcs Nagy
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