On Fri, Sep 09, 2016 at 05:01:19PM -0600, Jeff Law wrote: > On 09/09/2016 02:41 PM, Segher Boessenkool wrote: > >On Fri, Sep 09, 2016 at 12:31:31PM -0600, Jeff Law wrote: > >>On 06/08/2016 03:18 AM, Bernd Schmidt wrote: > >>>On 06/08/2016 03:47 AM, Segher Boessenkool wrote: > >>>>+ /* regrename creates wrong code for exception handling, if used > >>>>together > >>>>+ with separate shrink-wrapping. Disable for now, until we have > >>>>+ figured out what exactly is going on. */ > >>> > >>>That needs to be figured out now or it'll be there forever. > >>I suspect it's related to liveness computations getting out-of-wack with > >>separate shrink wrapping. If that's the case, then the question in my > >>mind is how painful is this going to be to fix in the df scanning code. > > > >I haven't been able to pin-point the failure. It happens for just a few > >huge testcases. So I am hoping someone who understands regrename will > >figure it out. > I think that's likely going to fall onto you :-) We don't generally > allow passes to just get disabled because some other pass causes them to > generate the wrong code.
We can instead declare that anyone enabling regrename is on his own? I like that plan better. I can also make the compiler error out if you try to have both separate shrink-wrapping and regrename on at the same time. There are no happy answers :-( > Though I'm curious how you triggered this -- regrename isn't enabled by > default (except for that brief window earlier this year...). Yes, these patches are that old now already. I also enabled regrename by default for quite a while, for testing purposes, since at the time it looked like regrename would be on by default for most architectures. Separate shrink-wrapping is supposed to be useful for all ports, not just for Power. Segher
