Re: Invalid reload inheritance with paradoxical subregs

["Joern Rennecke" <joernr@arc.com>]

On Thu, Apr 02, 2009 at 12:51:55PM +0200, Uros Bizjak wrote:
> I guess that somehow we have to prevent choose_reload_regs to blindly
> substitute memory_operand with register when paradoxical subregs are
> involved. The condition for the substitution should be similar to the
> condition in nonzero_bits1 from final.c:


Yes.  It would be nicer if we could get rid of these special meanings
of paradoxical subregs and instead used ZERO_EXTEND and SIGN_EXTEND in
their place; this would also give better code for target that can
have either of these.  However, that would not only require changes to
reload to reload these properly, but also to all the affected targets,
e.g. rtx_costs would have to discount the cost of the extension operation. 
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