On 07/05/2011 01:54 AM, Alan Modra wrote:
> Before that, fwprop never tries to work on hard registers.
I question this claim. It seems to me that fwprop did look at
paradoxical subregs of hard regs before my change.
That wasn't part of the design anyway. The main purpose of fwprop's
paradoxical subreg propagation is to get rid of back-to-back
SI-to-QI-to-SI conversions, and working with pseudos is enough.
The patch is okay as far as I'm concerned, but I'm not a maintainer of
fwprop. Perhaps it could be conditionalized on SMALL_REGISTER_CLASSES
(that's the source of the bug, I think: the single-register class "D"
conflicts with an argument register) but I don't think it's worth it.
Paolo
