On Aug 1, 2012, at 16:04 , Ulrich Weigand wrote: > I've been wondering about mode_dependent_address_p myself. It currently > appears to cover two quite separate questions: > > - If I have a valid address, will it remain valid if I change its mode to > something else? > > - If I have a valid address, and change it mode (resulting in another > valid address), will the two address expressions have different > "meanings" or side effects? (E.g. an auto-increment address where > the increment depends on the mode size.) > > It seems to me that the first of those questions is rather redundant. > Instead of speculating whether the address would remain valid if the > mode were changed, code should IMO rather simply just change the > address and then check its validity in the usual way (legitimate > address etc.). Only the second question really provides any actual > *new* information ... > > See also the reload patch I recently posted to get rid of some uses > of offsettable_memref_p in favor of simply doing the change and testing > its validity afterwards: > http://gcc.gnu.org/ml/gcc-patches/2012-07/msg01421.html
I think I see and need to give this further thought ... Thanks for your feedback :-) Cheers, Olivier