From: Joseph Myers <joseph@codesourcery.com>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: Szabolcs Nagy <szabolcs.nagy@arm.com>,
Vineet Gupta <Vineet.Gupta1@synopsys.com>,
"libc-alpha@sourceware.org" <libc-alpha@sourceware.org>
Subject: Re: [COMMITTED] arm: update libm test ulps
Date: Tue, 13 Apr 2021 18:02:07 +0000 [thread overview]
Message-ID: <alpine.DEB.2.22.394.2104131800320.30343@digraph.polyomino.org.uk> (raw)
In-Reply-To: <6fd7e855-3de3-3044-d56e-14ca1f0cd717@linaro.org>
On Tue, 13 Apr 2021, Adhemerval Zanella via Libc-alpha wrote:
> The math/libm-test-support.c imposes maximum ulp limits depending of
> the underling type:
>
> 228 if (testing_ibm128)
> 229 /* The documented accuracy of IBM long double division is 3ulp
> 230 (see libgcc/config/rs6000/ibm-ldouble-format), so do not
> 231 require better accuracy for libm functions that are exactly
> 232 defined for other formats. */
> 233 max_valid_error = exact ? 3 : 16;
> 234 else
> 235 max_valid_error = exact ? 0 : 9;
>
> And if I recall correctly there was a suggestion to consolidate and/or
> remove the ulps file altogether and use the maximum valid error as the
> threshold to report regressions. The only drawback I see of moving
> towards it is each architecture won't see if some change has degraded
> the function precision.
And for some of the higher ulps values it might be good to improve the
precision, which suggests having at least per-format if not
per-architecture empirical bounds for each function.
--
Joseph S. Myers
joseph@codesourcery.com
prev parent reply other threads:[~2021-04-13 18:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-08 8:58 Szabolcs Nagy
2021-04-11 18:04 ` Vineet Gupta
2021-04-13 9:52 ` Szabolcs Nagy
2021-04-13 15:01 ` Adhemerval Zanella
2021-04-13 18:02 ` Joseph Myers [this message]
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