From: Eli Zaretskii <eliz@gnu.org>
To: Andreas Schwab <schwab@linux-m68k.org>
Cc: 18995@debbugs.gnu.org, haroogan@gmail.com
Subject: bug#18995: Error: Could not reserve dynamic heap area.
Date: Sun, 09 Nov 2014 19:14:58 +0200 [thread overview]
Message-ID: <831tpcpa7h.fsf@gnu.org> (raw)
In-Reply-To: <87r3xcqqlp.fsf@igel.home>
> From: Andreas Schwab <schwab@linux-m68k.org>
> Cc: eliz@gnu.org, haroogan@gmail.com
> Date: Sun, 09 Nov 2014 17:35:30 +0100
>
> Eli Zaretskii <eliz@gnu.org> writes:
>
> > It looked like a GCC bug at first, but as I tried to modify the source
> > and look at the effect of that on the generated code, it finally
> > dawned on me: GCC's loop-unrolling code simply correctly calculated
> > that with the initial value of 0x68000000 and decrement of 0x00800000,
> > the value of 'size' in the loop will never be less than 0x00100000,
> > due to wraparound in the subtraction of unsigned values.
>
> Before wraping around, size will become zero, which is definitely less
> than 0x00100000.
Right, so it could be pure GCC bug after all.
For the record, the problem also goes away if 'size' is declared
ptrdiff_t, and nothing else is changed. So whatever the reason, it
definitely is somehow related to unsigned arithmetics.
prev parent reply other threads:[~2014-11-09 17:14 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-08 15:22 bug#18995: Error: Could not reserve dynamic heap area Alexander Shukaev
2014-11-08 17:29 ` Eli Zaretskii
2014-11-08 18:17 ` Alexander Shukaev
2014-11-08 18:30 ` Eli Zaretskii
2014-11-08 18:40 ` Alexander Shukaev
2014-11-08 18:57 ` Eli Zaretskii
2014-11-08 19:16 ` Alexander Shukaev
2014-11-08 19:50 ` Eli Zaretskii
2014-11-08 19:58 ` Alexander Shukaev
2014-11-08 20:05 ` Eli Zaretskii
2014-11-08 20:49 ` Daniel Colascione
2014-11-09 16:12 ` Eli Zaretskii
2014-11-09 16:30 ` Andreas Schwab
2014-11-09 16:47 ` Eli Zaretskii
[not found] ` <545F94E4.5060102@dancol.org>
2014-11-09 16:30 ` Alexander Shukaev
[not found] ` <837fz4pc4o.fsf@gnu.org>
2014-11-09 16:40 ` Daniel Colascione
2014-11-09 16:35 ` Andreas Schwab
2014-11-09 16:39 ` Alexander Shukaev
2014-11-09 16:49 ` Eli Zaretskii
2014-11-09 16:53 ` Alexander Shukaev
2014-11-09 17:17 ` Eli Zaretskii
2014-11-09 17:14 ` Eli Zaretskii [this message]
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