gcc bootstrap broken on i686-linux-gnu

[Roger Sayle]

Hi Graham,
> I think Roger's patch just tickles a problem in the x86 backend.
>
> register_operand may also match SUBREG which isn't valid for the
> REGNO macro hence the abort when enable checking is enabled.
>
> I think the uses of FP_REGNO_P (REGNO (...)) should be FP_REG_P (...)
> which checks it's operand is a REG before checking the REGNO.
>
> I've got such a patch in the works.

Excellent.  Many thanks.  I've just posted to the gcc list mentioning
my hypothesis that it could be the i386.md patterns at fault.

Roger
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