From: Joseph Myers <joseph@codesourcery.com>
To: Tamar Christina <Tamar.Christina@arm.com>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>,
"jakub@redhat.com" <jakub@redhat.com>,
"rguenther@suse.de" <rguenther@suse.de>,
"law@redhat.com" <law@redhat.com>, nd <nd@arm.com>
Subject: Re: [PATCH] Optimise the fpclassify builtin to perform integer operations when possible
Date: Mon, 12 Sep 2016 22:33:00 -0000 [thread overview]
Message-ID: <alpine.DEB.2.20.1609122222300.25218@digraph.polyomino.org.uk> (raw)
In-Reply-To: <VI1PR0801MB2031BC0C70CCAD966A9B2933FFFF0@VI1PR0801MB2031.eurprd08.prod.outlook.com>
On Mon, 12 Sep 2016, Tamar Christina wrote:
> Hi All,
>
> This patch adds an optimized route to the fpclassify builtin
> for floating point numbers which are similar to IEEE-754 in format.
Similar changes may be useful for __builtin_isfinite, __builtin_isnan,
__builtin_isinf, __builtin_isinf_sign, __builtin_isnormal.
Will your version always use only integer operations if the format is IEEE
enough? If so, it could be used by glibc's <math.h> if __SUPPORT_SNAN__
(-fsignaling-nans), except in the case where IBM long double is supported,
whereas presently all those built-in functions are avoided by glibc
<math.h> for -fsignaling-nans. The same applies to integer versions of
the other functions - whether or not they are beneficial in performance
normally, they are correct for -fsignaling-nans, which the present
built-in functions aren't.
(I intend to add issubnormal and iszero macros to glibc following TS
18661-1; built-in versions of those would be useful as well.)
--
Joseph S. Myers
joseph@codesourcery.com
next prev parent reply other threads:[~2016-09-12 22:28 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-12 16:21 Tamar Christina
2016-09-12 22:33 ` Joseph Myers [this message]
2016-09-13 12:25 ` Tamar Christina
2016-09-12 22:41 ` Joseph Myers
2016-09-13 12:30 ` Tamar Christina
2016-09-13 12:44 ` Joseph Myers
2016-09-15 9:08 ` Tamar Christina
2016-09-15 11:21 ` Wilco Dijkstra
2016-09-15 12:56 ` Joseph Myers
2016-09-15 13:05 ` Joseph Myers
2016-09-12 22:49 ` Joseph Myers
2016-09-13 12:33 ` Tamar Christina
2016-09-13 12:48 ` Joseph Myers
2016-09-13 8:58 ` Jakub Jelinek
2016-09-13 16:16 ` Jeff Law
2016-09-14 8:31 ` Richard Biener
2016-09-15 16:02 ` Jeff Law
2016-09-15 16:28 ` Richard Biener
2016-09-16 19:53 ` Jeff Law
2016-09-20 12:14 ` Tamar Christina
2016-09-20 14:52 ` Jeff Law
2016-09-20 17:52 ` Joseph Myers
2016-09-21 7:13 ` Richard Biener
2016-09-19 22:43 ` Michael Meissner
[not found] ` <41217f33-3861-dbb8-2f11-950ab30a7021@arm.com>
2016-09-20 21:27 ` Michael Meissner
2016-09-21 2:05 ` Joseph Myers
2016-09-21 8:32 ` Richard Biener
2016-09-12 17:24 Moritz Klammler
2016-09-12 20:08 ` Andrew Pinski
2016-09-13 12:16 Wilco Dijkstra
2016-09-13 16:10 ` Joseph Myers
2016-09-21 14:51 ` Richard Earnshaw (lists)
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