Jakub Jelinek <ja...@redhat.com> writes: > On Mon, Jan 04, 2016 at 03:25:48PM -0800, H.J. Lu wrote: >> LRA is fine. I should use >> >> (define_memory_constraint "Bm" >> "@internal Vector memory operand." >> (match_operand 0 "vector_memory_operand")) >> >> instead of >> >> (define_constraint "Bm" >> "@internal Vector memory operand." >> (match_operand 0 "vector_memory_operand")) > > I don't think so. At least the documentation says that > define_memory_constraint is for MEM constraints where if they are not > satisfied they can be made to satisfy by forcing the address into a > register. But that is not the case here, if a MEM is misaligned, no > equivalent changes to the XEXP (mem, 0) will make it aligned.
Yeah. It seems like a missing feature though. Maybe define_memory_constraint should have two conditions, one for when the MEM is valid and one for when the address is? Guess that isn't stage 3 material though. And maybe longer-term we should avoid define_memory_constraint altogether and have an automatic way of testing whether replacing the address with a register is OK. Thanks, Richard
