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From: Richard Earnshaw <rearnsha@gcc.gnu.org>
To: Joern Rennecke <joern.rennecke@superh.com>
Cc: Dave Korn <dk@artimi.com>, gcc@gcc.gnu.org
Subject: Re: Lousy scheduling decisions owing to bad interaction between sched and greg :(
Date: Fri, 03 Sep 2004 14:42:00 -0000	[thread overview]
Message-ID: <1094222545.1833.227.camel@pc960.cambridge.arm.com> (raw)
In-Reply-To: <200409031329.i83DTcJ23009@chloe.uk.w2k.superh.com>

On Fri, 2004-09-03 at 14:29, Joern Rennecke wrote:
> > ===================================================================
> >  4) Does an expander sound like the right solution to the problem? 
> > ===================================================================
> 
> Yes.  You'll also have to have an insn predicate for movsi that rejects
> memory-memory moves to prevent the rtl optimizers from generating them.

It can't really be a predicate (in the strict sense) because they can
only validate one operand.  Instead you need a final condition on the
insn that rejects it in the case where both operands turn out to be
memory operands.  The ARM does this for its mov<mm> patterns as, I
suspect, do several ports.

R.

  reply	other threads:[~2004-09-03 14:42 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-03 12:52 Dave Korn
2004-09-03 13:26 ` Joern Rennecke
2004-09-03 14:42   ` Richard Earnshaw [this message]
2004-09-03 16:35 ` Jeffrey A Law
2004-09-03 17:26   ` Lousy scheduling decisions owing to bad interaction betweensched " Dave Korn

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