On Sun, Mar 31, 2019 at 01:25:50PM -0400, Paul Koning wrote: > > > > On Mar 30, 2019, at 5:03 AM, co...@sdf.org wrote: > > > > hi folks, > > > > i was interesting in tackling some problems gcc netbsd/vax has. > > it has some ICEs which are in reload phase. searching around, the answer > > to that is "switch to LRA first". Now, I don't quite know what that is > > yet, but I know I need to try to do it. > > That's not quite the whole story. > > The answer is (1) switch from CC0 to CCmode condition code handling, which > enables (2) switch from Reload to LRA. > > (1) requires actual work, not terribly hard but not entirely trivial. (2) > may take as little as switching the "use LRA" flag to "yes". > > I did (1) as well as a tentative (2) for pdp11 last year. It was reasonably > straightforward thanks to a pile of help from Eric Botcazou and his gcc wiki > articles on the subject. You might find the pdp11 deltas for CCmode helpful > as a source of ideas, since the two machines have a fair amount in common as > far as condition codes goes. At least for the integer ops (pdp11 has > separate floating point conditions, vax doesn't). > > paul >
Hi paul! I have been reading on this, so now I have a draft that compiles the world's simplest C code (and nothing more, it will crash), but using CCmode (I think). I am being inspired by your port (which is a good thing since I know I can ask questions about it :)) https://github.com/coypoop/gcc/commit/df135c019de33950c9997fdea3ce07c5c920384d (I know that it's wrong!)
