From: Michael Matz <matz@suse.de>
To: Richard Guenther <rguenther@suse.de>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] Make VRP optimize useless conversions
Date: Mon, 11 Jul 2011 14:04:00 -0000 [thread overview]
Message-ID: <Pine.LNX.4.64.1107111433350.14485@wotan.suse.de> (raw)
In-Reply-To: <alpine.LNX.2.00.1107111412220.810@zhemvz.fhfr.qr>
Hi,
On Mon, 11 Jul 2011, Richard Guenther wrote:
> The following actually works.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu.
>
> Can you double-check it?
Seems sensible. Given this:
short s;
int i;
for (s = 0; s <= 127; s++)
i += (signed char)(unsigned char)s;
return i;
(or similar), does it remove the conversions to signed and unsigned char
now? And does it _not_ remove them if the upper bound is 128, or the
lower bound is -1 ?
Similar (now with extensions):
signed char c;
unsigned u;
for (c = 1; c < 127; c++)
u += (unsigned)(int)c;
The conversion to int is not necessary; but it is when the lower bound
is -1.
Ciao,
Michael.
next prev parent reply other threads:[~2011-07-11 12:46 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-07 13:41 Richard Guenther
2011-07-07 15:59 ` Michael Matz
2011-07-08 10:44 ` Richard Guenther
2011-07-08 12:40 ` Michael Matz
2011-07-08 13:38 ` Richard Guenther
2011-07-11 12:23 ` Richard Guenther
2011-07-11 14:04 ` Michael Matz [this message]
2011-07-12 18:02 ` Build failure (Re: [PATCH] Make VRP optimize useless conversions) Ulrich Weigand
2011-07-13 8:43 ` Richard Guenther
2011-07-13 13:13 ` H.J. Lu
2011-07-13 13:57 ` Ulrich Weigand
2011-08-13 10:17 ` [PATCH] Make VRP optimize useless conversions H.J. Lu
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