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Re: Feature request: ability to describe x86 register halves as contraints.



  In message <199806301655.RAA04324@phal.cygnus.co.uk>you write:
  > >   > Is it possible to add such an extension to the constraints language? 
  > >   > Hopefully only minimal changes should be needed for this. 
  > > First there'd have to be a way to describe hi/lo halves of registers
  > > in RTL.  I'm not aware of any such mechanism.
  > 
  > I think we should change SUBREG to count addressable units instead of
  > 'words'.  This would also fix some brokenness when there are
  > varying register sizes (E.g. floating point wider than integer...)
I'm not sure I'd recommend changing the meaning of SUBREG -- we might
be better off with a new RTX for this kindof thing.

jeff


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