register renaming causes many ARM testsuite failures

[Michael Meissner]

On Wed, Jan 03, 2001 at 02:04:56PM -0800, Richard Henderson wrote:
> On Wed, Jan 03, 2001 at 07:57:51PM +0000, Philip Blundell wrote:
> > >The function build_def_use uses constraints to determine which registers can
> > >be used for renaming.  The relevant bit of code is this:
> > 
> > If I'm reading that right, it just notes which class an operand is in so
> > that it can later choose another register in the same class.  The problem
> > at hand here is that the actual registers in use, not just their classes,
> > matter in an ldmsi insn.  Am I missing something about the code you quoted?
> 
> He's right Bernd.  We're going to need some way to squash renaming
> in this case.  Probably through a new constraint token indicating
> that we shouldn't consider this operand for renaming.

Ideally we should rerun the condition and predicates for register renaming
(especially the condition which is the only place where you can check operands
against each other).

-- 
Michael Meissner, Red Hat, Inc.  (GCC group)
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