On Fri, Sep 10, 2021 at 11:09:31AM +0800, Hongtao Liu wrote: > On Fri, Sep 10, 2021 at 7:49 AM Segher Boessenkool > <seg...@kernel.crashing.org> wrote: > > way too long. But from that same history it follows that anything you > > do not super carefully (with testing everywhere) will cause some serious > Frankly, testing everywhere is too heavy a burden for developers, > after all, everyone has a limited variety of machines, and may not be > familiar with using other targets' simulators.
Your change should be tested on enough relevant targets that we can have confidence it works properly. That does not necessarily mean you have to test everywhere yourself (although that is greatly appreciated, makes life easier for everyone, including yourself, and as David points out the cfarm is a great help). So you didn't realise your patch would wreak havoc on most other targets than what you tested on. It happens, it helps if you can avoid it, but you learn only from things that go wrong :-) (The patch has still not been reverted btw. I'll do this later tonight if you don't). > And back to the problem we were trying to solve at the beginning > (subreg:HF(reg:SI)), I guess this is not just a problem in x86 > backend, any backend can encounter similar problems, that's why we > remove all the weird cases in validate_subreg. Expand should simply expand to two statements: one doing the real subreg, the other doing the bit_cast. Segher
