On Tue, Feb 15, 2022 at 11:01:03AM +0800, HAO CHEN GUI wrote: Hi! > On 15/2/2022 上午 5:36, Segher Boessenkool wrote: > > On Wed, Feb 09, 2022 at 10:43:17AM +0800, HAO CHEN GUI wrote: > > All that are arguments for expanding to split form, not for removing > > TImode from the iterator. And you leave PTImode, which *always* is in > > GPRs! > >From my understanding, PTImode has limitation that it needs to be assigned > with an even/odd register pair. So it can't be split before the reload pass.
TImode is put in an even/odd pair always as well. What is special about PTImode here? > Currently it is split after reload.> This prevents almost all optimisations. Splits after reload should be a last resort thing. They almost always cause bigger problems than what they are meant to solve. There aren't many splitters that *have* to run after RA! > > (You'll also have to show it is *correct*, you need to prove (or show it > > really likely :-) ) that after this change there are no TImode things > > generated anywhere (anywhere!) that are no longer handled now). > > > Yes, the TI may be generated after expand pass and causes ICEs. So how about > creating two mode iterators? One is for expand which doesn't include TImode, > another is for the split which include TImode and make TImode to be split > as early as possible? You can also have the expanders fail for TImode? That gives you a good place to put in a code comment as well ;-) Segher
