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From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: Richard Sandiford <Richard.Sandiford@arm.com>
Cc: Bu Le <cityubule@qq.com>, gcc-help <gcc-help@gcc.gnu.org>
Subject: Re: [AArch64][Spec2017]Question about mlow-precision-div optimization.
Date: Wed, 04 Mar 2020 13:26:00 -0000	[thread overview]
Message-ID: <AM5PR0801MB2035EE5222A0A960271E568983E50@AM5PR0801MB2035.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <mpta74xs91q.fsf@arm.com>

Hi Richard,

> The suggestion was to have a parameter to control the number of steps,
> rather than always use the values that are currently hard-coded into
> aarch64.c.
>
> That sounds OK in principle.  It would fix one of the downsides of the
> current code, in which users can force reciprocal approximation to be
> used at low precision, but can't force it to be used at the precisions
> normally chosen by -mtune.

Well there are only 2 possible settings, so I don't see how a param would be
reasonable... However given there is no performance improvement for the low
precision versions, what is the point of adding new options for the even slower,
higher precision variant?!?

Cheers,
Wilco

  reply	other threads:[~2020-03-04 13:26 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-25 15:27 Wilco Dijkstra
2020-02-26 13:01 ` =?gb18030?B?QnUgTGU=?=
2020-02-27 22:08   ` Wilco Dijkstra
2020-03-03 16:22     ` Richard Sandiford
2020-03-04 13:26       ` Wilco Dijkstra [this message]
     [not found]       ` <tencent_5C7FA4816F6BB9D3236327A73C9BA5A39105@qq.com>
2020-03-06 15:24         ` 回复: " Richard Sandiford
  -- strict thread matches above, loose matches on Subject: below --
2020-02-23  4:06 Bu Le

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