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Re: Improve things for PR71724, in combine/if_then_else_cond
On Fri, Jan 20, 2017 at 01:24:15PM -0600, Segher Boessenkool wrote:
> On Fri, Jan 20, 2017 at 01:33:59PM +0100, Bernd Schmidt wrote:
> > So, when looking for situations where we have only one condition, we can
> > try to undo the conversion of a plain REG into a condition, on the
> > grounds that this is probably less helpful.
> >
> > This seems to cure the testcase, but Segher also has a patch in the PR
> > that looks like a good and more direct approach. IMO both should be
> > applied. This one was bootstrapped and tested on x86_64-linux. Ok?
>
> My patch does not cure all problems, it simply simplifies things a bit
> better; but the same is true for your patch if I read it correctly.
>
> Okay for trunk, and I'll do my half as well. Thanks,
It turns out my patch (see the PR) causes (or at least triggers)
miscompilations on tilegx. I will drop it for now.
Longer term we will have to fix this whole if_then_else_cond business,
maybe make it less expensive and/or more effective as well.
Segher