From: Michael Hudson-Doyle <michael.hudson@canonical.com>
To: Andreas Schwab <schwab@suse.de>
Cc: Michael Hudson-Doyle via Libc-alpha <libc-alpha@sourceware.org>
Subject: Re: [PATCH v2] Avoid undefined behaviour in ibm128 implementation of llroundl
Date: Mon, 22 Aug 2022 20:52:03 +1200 [thread overview]
Message-ID: <CAJ8wqteD8S9tznu_9WLE+gLREtVQZZcyVsGWzU1ez+DmP-nh1A@mail.gmail.com> (raw)
In-Reply-To: <mvmsfloekxp.fsf@suse.de>
On Mon, 22 Aug 2022, 20:34 Andreas Schwab, <schwab@suse.de> wrote:
> On Aug 22 2022, Michael Hudson-Doyle via Libc-alpha wrote:
>
> > @@ -69,7 +70,7 @@ __llroundl (long double x)
> > res = hi + lo;
>
> The overflow happens here. Changing the type of the LHS does not change
> that.
>
IIRC it was one of the "res += 1"s lower down in the test case that was
failing for me. But maybe a more thorough rewrite of this function is
called for (if people still care about ibm128 I guess).
Cheers,
mwh
--
> Andreas Schwab, SUSE Labs, schwab@suse.de
> GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
> "And now for something completely different."
>
prev parent reply other threads:[~2022-08-22 8:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-21 10:44 [PATCH] " Michael Hudson-Doyle
2022-08-21 19:24 ` Michael Hudson-Doyle
2022-08-22 2:04 ` [PATCH v2] " Michael Hudson-Doyle
2022-08-22 7:54 ` Florian Weimer
2022-08-22 8:34 ` Andreas Schwab
2022-08-22 8:52 ` Michael Hudson-Doyle [this message]
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