From: Joseph Myers <joseph@codesourcery.com>
To: <vladimir.mezentsev@oracle.com>
Cc: <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] PR libgcc/59714 complex division is surprising on aarch64
Date: Wed, 25 Oct 2017 17:29:00 -0000 [thread overview]
Message-ID: <alpine.DEB.2.20.1710251726070.11032@digraph.polyomino.org.uk> (raw)
In-Reply-To: <1508952211-12992-1-git-send-email-vladimir.mezentsev@oracle.com>
On Wed, 25 Oct 2017, vladimir.mezentsev@oracle.com wrote:
> +# Disable FMA (floating-point multiply-add) instructions for complex division.
> +# These instructions can produce different result if two operations executed separately.
> +LIBGCC2_FFP_CONTRAST_CFLAGS = -ffp-contract=off
> +LIB2_DIV3_FUNCS = _divdc3 _divhc3 _divsc3
Without regard to whether the change is appropriate in the first place,
I'm doubtful of the logic for selecting floating-point modes. I'd expect
something that applies to all floating-point modes. Even if nothing has
fused XFmode operations, some architectures (e.g. s390, powerpc) have
fused operations on TFmode / KFmode.
--
Joseph S. Myers
joseph@codesourcery.com
next prev parent reply other threads:[~2017-10-25 17:29 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-25 17:29 vladimir.mezentsev
2017-10-25 17:29 ` Joseph Myers [this message]
2017-10-25 19:19 ` vladimir.mezentsev
2017-10-25 20:04 ` Joseph Myers
-- strict thread matches above, loose matches on Subject: below --
2018-02-06 7:20 vladimir.mezentsev
2018-02-06 16:53 ` Joseph Myers
2018-02-07 0:25 ` vladimir.mezentsev
2018-02-07 0:31 ` Joseph Myers
2018-01-25 20:40 vladimir.mezentsev
2018-01-26 3:39 ` Joseph Myers
2018-01-29 20:54 ` vladimir.mezentsev
2018-01-29 21:01 ` Joseph Myers
2018-02-06 8:55 ` vladimir.mezentsev
2018-02-06 17:13 ` Joseph Myers
2017-10-19 13:20 Wilco Dijkstra
2017-10-19 13:52 ` Richard Earnshaw (lists)
2017-10-19 17:13 ` Vladimir Mezentsev
2017-10-19 17:24 ` Wilco Dijkstra
2017-10-25 3:26 ` vladimir.mezentsev
2017-10-18 21:32 vladimir.mezentsev
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