From: Joseph Myers <joseph@codesourcery.com>
To: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: "linux-snps-arc@lists.infradead.org"
<linux-snps-arc@lists.infradead.org>,
"libc-alpha@sourceware.org" <libc-alpha@sourceware.org>,
Adhemerval Zanella <adhemerval.zanella@linaro.org>
Subject: Re: ARC math test regressions (was Re: [PATCH v7 00/13] glibc port to ARC processors)
Date: Thu, 2 Jul 2020 16:27:25 +0000 [thread overview]
Message-ID: <alpine.DEB.2.21.2007021618480.21468@digraph.polyomino.org.uk> (raw)
In-Reply-To: <4a04f8dc-c888-1411-0add-8603822d5ee4@synopsys.com>
On Thu, 2 Jul 2020, Vineet Gupta via Libc-alpha wrote:
> Now acos can come from 2 places depending on LIBM_SVID_COMPAT
> - math/w_acos_template.c <-- sets errno only
This wrapper, unlike the compat one, always calls __ieee754_acos
(appropriately suffixed), relying on it to raise appropriate exceptions.
The implementation in sysdeps/ieee754/dbl-64/e_asin.c raises the exception
by doing an Inf / Inf computation.
u.i[HIGH_HALF]=0x7ff00000;
v.i[HIGH_HALF]=0x7ff00000;
u.i[LOW_HALF]=0;
v.i[LOW_HALF]=0;
return u.x/v.x;
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95115
The right place to fix this is in GCC, to stop it constant-folding Inf /
Inf when flag_trapping_math. That should be a straightforward fix.
It would also be reasonable to change the above code to just "return 0.0 /
0.0;", as a simpler, more idiomatic way of returning a NaN with "invalid"
raised. (Any code constructing infinities / NaNs via bit patterns likely
predates built-in functions that can be used to represent such values
directly. Though the GCC bug means a literal replacement with "return
__builtin_inf () / __builtin_inf ();" wouldn't fix the present problem.)
--
Joseph S. Myers
joseph@codesourcery.com
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next prev parent reply other threads:[~2020-07-02 16:27 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-15 20:14 [PATCH v7 00/13] glibc port to ARC processors Vineet Gupta
2020-06-15 20:14 ` [PATCH v7 01/13] ARC: ABI Implementation Vineet Gupta
2020-07-01 0:06 ` [PATCH v7.1 " Vineet Gupta
[not found] ` <b6322150-240a-5f06-b700-83e3eb79deec@linaro.org>
2020-07-01 19:36 ` Vineet Gupta
2020-07-01 19:45 ` Adhemerval Zanella
2020-06-15 20:14 ` [PATCH v7 02/13] ARC: startup and dynamic linking code Vineet Gupta
2020-06-15 20:14 ` [PATCH v7 03/13] ARC: Thread Local Storage support Vineet Gupta
2020-07-01 0:07 ` [PATCH v7.1 " Vineet Gupta
2020-06-15 20:14 ` [PATCH v7 04/13] ARC: Atomics and Locking primitives Vineet Gupta
2020-06-15 20:14 ` [PATCH v7 05/13] ARC: math soft float support Vineet Gupta
2020-06-15 20:14 ` [PATCH v7 06/13] ARC: hardware floating point support Vineet Gupta
2020-07-01 0:08 ` [PATCH v7.1 " Vineet Gupta
2020-06-15 20:14 ` [PATCH v7 07/13] ARC: Linux Syscall Interface Vineet Gupta
2020-07-01 0:08 ` [PATCH v7.1 " Vineet Gupta
[not found] ` <e9e2ae28-cd78-5924-c1fa-52b1499c245a@linaro.org>
2020-07-04 3:54 ` Vineet Gupta
2020-07-06 13:20 ` Adhemerval Zanella
2020-07-07 1:25 ` Vineet Gupta
2020-07-07 19:24 ` Adhemerval Zanella
2020-07-07 20:55 ` [PATCH v7.2 " Vineet Gupta
[not found] ` <b64d0df1-4229-d619-0ab1-ded287323775@linaro.org>
2020-07-08 19:32 ` Vineet Gupta
2020-07-09 16:03 ` Adhemerval Zanella
2020-07-09 16:24 ` Vineet Gupta
2020-07-09 16:25 ` Adhemerval Zanella
2020-07-09 21:13 ` Vineet Gupta
2020-07-09 21:36 ` ARC testsuite regressions (was Re: [PATCH v7.2 07/13] ARC: Linux Syscall Interface) Vineet Gupta
2020-07-09 22:01 ` Alistair Francis
2020-07-09 22:16 ` Vineet Gupta
2020-07-10 9:28 ` Florian Weimer
2020-07-10 15:53 ` Vineet Gupta
2020-07-10 17:02 ` Florian Weimer
2020-07-10 20:07 ` Vineet Gupta
2020-07-10 20:32 ` Florian Weimer
2020-07-10 19:12 ` Alistair Francis
2020-07-10 20:33 ` Florian Weimer
2020-07-10 20:56 ` Alistair Francis
2020-07-10 19:10 ` Alistair Francis
2020-07-07 21:07 ` [PATCH v7.1 07/13] ARC: Linux Syscall Interface Vineet Gupta
2020-07-07 21:32 ` Joseph Myers
2020-07-07 23:16 ` Vineet Gupta
2020-06-15 20:14 ` [PATCH v7 08/13] ARC: Linux ABI Vineet Gupta
2020-06-15 20:14 ` [PATCH v7 09/13] ARC: Linux Startup and Dynamic Loading Vineet Gupta
2020-06-15 20:14 ` [PATCH v7 10/13] ARC: ABI lists Vineet Gupta
2020-07-01 0:09 ` [PATCH v7.1 " Vineet Gupta
2020-06-15 20:14 ` [PATCH v7 11/13] ARC: Build Infrastructure Vineet Gupta
2020-07-03 17:09 ` Adhemerval Zanella
2020-06-15 20:14 ` [PATCH v7 12/13] build-many-glibcs.py: Enable ARC builds Vineet Gupta
2020-07-03 17:37 ` Adhemerval Zanella
2020-06-15 20:14 ` [PATCH v7 13/13] Documentation for ARC port Vineet Gupta
2020-07-03 17:38 ` Adhemerval Zanella
2020-06-23 16:56 ` [PATCH v7 00/13] glibc port to ARC processors Vineet Gupta
2020-07-01 0:11 ` Vineet Gupta
2020-07-01 1:44 ` Adhemerval Zanella
2020-07-01 19:13 ` Vineet Gupta
2020-07-02 1:00 ` ARC math test regressions (was Re: [PATCH v7 00/13] glibc port to ARC processors) Vineet Gupta
2020-07-02 7:17 ` Andreas Schwab
2020-07-02 16:27 ` Joseph Myers [this message]
2020-07-02 17:45 ` Vineet Gupta
2020-07-02 21:27 ` [PATCH v7 00/13] glibc port to ARC processors Joseph Myers
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