From: Alan Modra <amodra@gmail.com>
To: Iain Buclaw <ibuclaw@gdcproject.org>
Cc: gcc-patches@gcc.gnu.org, Ian Lance Taylor <ian@airs.com>
Subject: Re: ubsan: d-demangle.c:214 signed integer overflow
Date: Mon, 7 Sep 2020 10:26:50 +0930 [thread overview]
Message-ID: <20200907005650.GW15695@bubble.grove.modra.org> (raw)
In-Reply-To: <1599234463.wegd8hf5fw.astroid@galago.none>
On Fri, Sep 04, 2020 at 06:23:10PM +0200, Iain Buclaw wrote:
> If we're already using limits.h, I guess it should be fine to also add
>
> #define UINT_MAX ((unsigned) ~0U)
Yes, except that I'll use the simpler fall-back
#define UINT_MAX (~0U)
The habit of using a cast for unsigned constants dates back to K&R C
where a U suffix was not valid. For example, from libiberty/strtol.c
#define ULONG_MAX ((unsigned long)(~0L))
Since the code uses ISO/ANSI C features such as prototypes I think
we're OK with a U suffix. And if there's something I'm missing then
#define UINT_MAX ((unsigned) ~0)
would be correct for K&R.
> I'll leave it to your judgement on that though.
>
> Other than that, OK from me.
Do I need an OK from Ian too?
--
Alan Modra
Australia Development Lab, IBM
next prev parent reply other threads:[~2020-09-07 0:56 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-03 13:01 Alan Modra
2020-09-03 21:02 ` Iain Buclaw
2020-09-04 0:59 ` Alan Modra
2020-09-04 11:22 ` Iain Buclaw
2020-09-04 13:34 ` Alan Modra
2020-09-04 16:23 ` Iain Buclaw
2020-09-07 0:56 ` Alan Modra [this message]
2020-09-07 16:17 ` Iain Buclaw
2020-09-07 17:46 ` Ian Lance Taylor
2020-11-13 19:04 ` Jeff Law
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