On Tue, Oct 27, 2020 at 10:35:59AM +0000, Alex Coplan wrote: > On 26/10/2020 12:43, Segher Boessenkool wrote: > > I do not like handling both mult and ashift in one case like this, it > > complicates things for no good reason. Write it as two cases, and it > > should be good. > > OK, the attached patch rewrites (mult x 2^n) to (ashift x n) at the top > of make_extraction so that the existing ASHIFT block can do the work for > us. We remember if we did it and then convert it back if necessary. > > I'm not convinced that it's an improvement. What do you think?
Restoring it like that is just yuck. That can be okay if it is as the start and end of a smallish function, importantly some self-contained piece of code, but this is not. Just write it as two blocks? One handling the shift, that is already there; and add one block adding the mult case. That should not increase the complexity of this already way too complex code. Segher
