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Re: Fix for GCC Bugzilla Bug 36133
- From: Andreas Schwab <schwab at suse dot de>
- To: "Gunnar Von Boehn" <gunnar at genesi-usa dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Tue, 17 Jun 2008 13:53:38 +0200
- Subject: Re: Fix for GCC Bugzilla Bug 36133
- References: <b989d750806060633v27924455t3d0ec17ae336865a@mail.gmail.com>
"Gunnar Von Boehn" <gunnar@genesi-usa.com> writes:
> Please apply the patch and recompile.
> GCC is now aware that the LSR instruction does set the CC already and
> will not create the unneeded TST.
That does not look correct, see the comment in notice_update_cc:
case ASHIFT: case ASHIFTRT: case LSHIFTRT:
case ROTATE: case ROTATERT:
/* These instructions always clear the overflow bit, and set
the carry to the bit shifted out. */
/* ??? We don't currently have a way to signal carry not valid,
nor do we check for it in the branch insns. */
CC_STATUS_INIT;
break;
Andreas.
--
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
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