[PATCH] middle-end: fix de-optimizations with bitclear patterns on signed values

[Jonathan Wakely]

On Tue, 26 Oct 2021 at 20:40, Jakub Jelinek wrote:

> On Tue, Oct 26, 2021 at 08:35:40PM +0100, Jonathan Wakely wrote:
> > We can change __cmp_cat::type if that would result in better code. I
> picked
> > signed char because we only need two bits, and preferably have a signed
> > type as it simplifies some things. Would int make more sense? Or int:2 ?
>
> I think signed char is fine (and changing it would be an ABI change),


We haven't committed to a C++20 ABI yet, so changes are possible. If we
don't need to change, that's obviously preferable.


> int is
> unnecessarily large and int:2 would be certainly slower (and harder).
>

OK, signed char it is then.