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Re: new register allocator and HARD_REGNO_CALL_PART_CLOBBERED
- From: Joern Rennecke <joern dot rennecke at superh dot com>
- To: Michael Matz <matz at suse dot de>
- Cc: 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: Wed, 14 May 2003 12:58:39 +0100
- Subject: Re: new register allocator and HARD_REGNO_CALL_PART_CLOBBERED
- Organization: SuperH UK Ltd.
- References: <Pine.LNX.4.44.0305132146300.15564-100000@wotan.suse.de>
Michael Matz wrote:
> I want to ensure that I understand the problem correctly, so please
> correct me if I'm wrong.
>
> The problem is, that some hardregs are not allowed for pseudos live
> over calls, i.e. a subset of the caller-saved-regs-problem, _but_:
> 1) this set depends on the mode of the actual pseudo, and
Yes.
> 2) this set can change for each call, i.e. depends on the actual call.
It's not really the call that might be different, but if a different pseudo
is tracked across a different call, you have to consider the mode of that
other pseudo. This is relevant if you want to merge webs for different
pseudos.
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