On 02/08/2012 01:12 PM, Richard Guenther wrote: > On Wed, Feb 8, 2012 at 1:02 PM, Bernd Schmidt <ber...@codesourcery.com> wrote: >> On 02/07/2012 11:33 PM, Steven Bosscher wrote: >>> On Tue, Feb 7, 2012 at 11:19 PM, Ramana Radhakrishnan >>> <ramana.radhakrish...@linaro.org> wrote: >>>> Hi Andrew >>>> >>>> I find it interesting that cond_exec's in this form survive all the >>>> way till reload and "work". AFAIK we could never have cond_exec's >>>> before reload . >>> >>> There is nothing wrong per-se with cond_execs before reload, as long >>> as you don't have to reload a predicate pseudo-reg. >> >> I thought the problem was that we'd have to emit conditional reload >> insns and inheritance wouldn't work. > > It probably depends on how DF sees conditional uses / defs. If they > look like regular uses / defs then I suppose un-conditional spills/reloads > are fine - otherwise of course you'd corrupt one of the two register set > states.
I'm pretty sure conditional defs are always RMW, but I'd have to go look. Can't imagine it working otherwise though. Bernd
