From: Joseph Myers <joseph@codesourcery.com>
To: Tamar Christina <Tamar.Christina@arm.com>
Cc: Jeff Law <law@redhat.com>, GCC Patches <gcc-patches@gcc.gnu.org>,
Wilco Dijkstra <Wilco.Dijkstra@arm.com>,
"rguenther@suse.de" <rguenther@suse.de>,
Michael Meissner <meissner@linux.vnet.ibm.com>, nd <nd@arm.com>
Subject: Re: [PATCH][GCC][PATCHv3] Improve fpclassify w.r.t IEEE like numbers in GIMPLE.
Date: Thu, 15 Dec 2016 19:37:00 -0000 [thread overview]
Message-ID: <alpine.DEB.2.20.1612151858040.2106@digraph.polyomino.org.uk> (raw)
In-Reply-To: <VI1PR0801MB20311CC45C387326291E49F1FF9D0@VI1PR0801MB2031.eurprd08.prod.outlook.com>
On Thu, 15 Dec 2016, Tamar Christina wrote:
> > Note that on some systems we even disable 64bit floating point support.
> > I suspect this check needs a little re-thinking as I don't think that
> > checking for a specific UNITS_PER_WORD is correct, nor is checking the
> > width of the type. I'm not offhand sure what the test should be, just
> > that I think we need something better here.
>
> I think what I really wanted to test here is if there was an integer
> mode available which has the exact width as the floating point one. So I
> have replaced this with just a call to int_mode_for_mode. Which is
> probably more correct.
I think an integer mode should always exist - even in the case of TFmode
on 32-bit systems (32-bit sparc / s390, for example, use TFmode long
double for GNU/Linux, and it's supported as _Float128 and __float128 on
32-bit x86). It just be not be usable for arithmetic or declaring
variables of that type.
I don't know whether TImode bitwise operations, such as generated by this
fpclassify work, will get properly lowered to operations on supported
narrower modes, but I hope so (clearly it's simpler if you can write
things straightforwardly and have them cover this case of TFmode on 32-bit
systems automatically through lowering elsewhere in the compiler, than if
covering that case would require additional code - the more cases you
cover, the more opportunity there is for glibc to use the built-in
functions even with -fsignaling-nans).
--
Joseph S. Myers
joseph@codesourcery.com
next prev parent reply other threads:[~2016-12-15 19:04 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-11 17:26 Tamar Christina
2016-11-11 22:06 ` Joseph Myers
2016-11-24 15:52 ` Tamar Christina
2016-11-24 18:28 ` Joseph Myers
2016-11-25 12:19 ` Tamar Christina
2016-12-02 16:20 ` Tamar Christina
2016-12-12 9:20 ` Tamar Christina
2016-12-12 15:53 ` Jeff Law
2016-12-14 8:07 ` Jeff Law
2016-12-15 10:16 ` Tamar Christina
2016-12-15 19:37 ` Joseph Myers [this message]
2016-12-19 17:24 ` Tamar Christina
2017-01-18 16:15 ` Jeff Law
2017-01-18 16:43 ` Joseph Myers
2017-01-18 16:55 ` Joseph Myers
2017-01-18 17:07 ` Joseph Myers
2017-01-19 14:44 ` Tamar Christina
2017-01-19 14:47 ` Joseph Myers
2017-01-19 15:26 ` Tamar Christina
2017-01-19 16:34 ` Joseph Myers
2017-01-19 18:06 ` Tamar Christina
2017-01-19 18:28 ` Joseph Myers
2017-01-23 15:55 ` Tamar Christina
2017-01-23 16:26 ` Joseph Myers
[not found] ` <5C66F854-5903-4F34-8DE6-5EE2E1FC5C77@gmail.com>
[not found] ` <VI1PR0801MB20316861AF6C0D8582A10069FF740@VI1PR0801MB2031.eurprd08.prod.outlook.com>
[not found] ` <VI1PR0801MB2031A5E562143B32E35ECFFEFF4B0@VI1PR0801MB2031.eurprd08.prod.outlook.com>
[not found] ` <VI1PR0801MB20317F959D3EEA166DC641E0FF450@VI1PR0801MB2031.eurprd08.prod.outlook.com>
[not found] ` <VI1PR0801MB20311246A73FD82A08541F26FF170@VI1PR0801MB2031.eurprd08.prod.outlook.com>
2017-05-15 10:39 ` Tamar Christina
2017-06-08 10:31 ` Markus Trippelsdorf
2017-06-08 12:00 ` Christophe Lyon
2017-06-08 12:21 ` Tamar Christina
2017-06-08 15:40 ` Tamar Christina
2017-06-08 15:43 ` Richard Biener
2017-06-08 16:44 ` Joseph Myers
2017-06-08 18:23 ` Richard Biener
2017-08-17 11:46 ` Tamar Christina
2017-08-23 13:19 ` Tamar Christina
2017-08-23 13:26 ` Richard Biener
2017-08-23 15:51 ` Tamar Christina
2017-08-24 11:01 ` Richard Biener
2017-08-29 11:25 ` Tamar Christina
2017-08-30 14:37 ` Richard Biener
2017-06-09 8:14 ` Tamar Christina
2016-12-19 20:34 ` Jeff Law
2017-01-03 9:56 ` Tamar Christina
2017-01-16 17:06 ` Tamar Christina
2017-06-09 0:27 David Edelsohn
2017-06-09 5:19 ` Joseph Myers
2017-06-09 8:12 ` Tamar Christina
2017-06-09 11:40 ` Rainer Orth
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