From: "Koning, Paul" <Paul.Koning@dell.com>
To: "cassio.neri@gmail.com" <cassio.neri@gmail.com>,
Cassio Neri via Gcc-patches <gcc-patches@gcc.gnu.org>
Cc: "libstdc++@gcc.gnu.org" <libstdc++@gcc.gnu.org>
Subject: Re: [PATCH] libstdc++: More efficient std::chrono::year::leap.
Date: Fri, 21 May 2021 18:05:14 +0000 [thread overview]
Message-ID: <34C4F25A-6333-4C08-BBFF-8E86A5A9B764@dell.com> (raw)
In-Reply-To: <CAOfgUPgc+4fZ65GtcprdiM+ObP6o-avP85frLzY0A1uqZHOoUg@mail.gmail.com>
> On May 21, 2021, at 1:46 PM, Cassio Neri via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
>
> Simple change to std::chrono::year::is_leap. If a year is multiple of 100,
> then it's divisible by 400 if and only if it's divisible by 16. The latter
> allows for better code generation.
I wonder if the optimizer could be taught to do that.
The change seems correct but it is very confusing; at the very least the reasoning you gave should be stated in a comment on that check.
paul
next prev parent reply other threads:[~2021-05-21 18:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-21 17:46 Cassio Neri
2021-05-21 18:05 ` Koning, Paul [this message]
2021-05-21 18:44 ` Cassio Neri
2021-06-23 11:45 ` Jonathan Wakely
2021-06-23 13:16 ` Jonathan Wakely
2021-06-23 17:51 ` Jonathan Wakely
2021-06-23 17:52 ` Jonathan Wakely
2021-06-24 11:42 ` Cassio Neri
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