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Re: condition codes, haifa-sched and virtual-stack-vars
- From: Alexandre Oliva <aoliva at redhat dot com>
- To: Greg McGary <greg at mcgary dot org>
- Cc: gcc at gcc dot gnu dot org
- Date: 30 Jan 2002 18:41:24 -0200
- Subject: Re: condition codes, haifa-sched and virtual-stack-vars
- Organization: GCC Team, Red Hat
- References: <200201301859.g0UIxx606426@kayak.mcgary.org>
On Jan 30, 2002, Greg McGary <greg@mcgary.org> wrote:
> Haifa-sched schedules the move from virtual-stack-vars between the
> bitfield test sequence and the branch. Later, global-reg alloc
> instantiates virtual-stack-vars as an offset from FP, so the move
> mutates into an add of fp+offset, clobbering the condition codes
> computed earlier in the bitfield test.
How about having a pre-reload move pattern that clobbers CC, split
after reload into one that does not, so that sched2 could put the move
between compare and branch should it indeed not affect CC?
--
Alexandre Oliva Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer aoliva@{cygnus.com, redhat.com}
CS PhD student at IC-Unicamp oliva@{lsd.ic.unicamp.br, gnu.org}
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