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Re: new register allocator and HARD_REGNO_CALL_PART_CLOBBERED
- From: Alexandre Oliva <aoliva at redhat dot com>
- To: Michael Matz <matz at suse dot de>
- Cc: Joern Rennecke <joern dot rennecke at superh dot com>, Daniel Berlin <dberlin at dberlin dot org>, Herman ten Brugge <hermantenbrugge at home dot nl>, Dale Johannesen <dalej at apple dot com>, <gcc at gcc dot gnu dot org>
- Date: 15 May 2003 16:07:04 -0300
- Subject: Re: new register allocator and HARD_REGNO_CALL_PART_CLOBBERED
- Organization: GCC Team, Red Hat
- References: <Pine.LNX.4.44.0305151301070.15564-100000@wotan.suse.de>
On May 15, 2003, Michael Matz <matz@suse.de> wrote:
> Sure. But then I would explicitely add the necessary clobbers (of
> subregs) to the call instructions, explicitely stating what happens,
> namely that some register parts will be destroyed, instead of an
> abstraction like HARD_REGNO_CALL_PART_CLOBBERED. At least for clobbers
> which can change per call.
Clobbering a subreg will still affects the entire register, if
BITS_PER_WORD is defined properly, so this is not an option. Besides,
you don't want to pollute calls with clobbers, otherwise why would we
have CALL_USED_REGISTERS in the first place?
--
Alexandre Oliva Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer aoliva@{redhat.com, gcc.gnu.org}
CS PhD student at IC-Unicamp oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist Professional serial bug killer