Olivier Hainque wrote: > I had made a proposal to help the rs6000_mode_dependent_address > issue, http://gcc.gnu.org/ml/gcc-patches/2012-04/msg01668.html. > > Seems to me that the general idea is still valid: > > << a number of places in the compiler use the > mode_dependent_address_p predicate to actually check for weaker necessary > conditions > >> > > Opinion on the proposal ?
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 Bye, Ulrich -- Dr. Ulrich Weigand GNU Toolchain for Linux on System z and Cell BE ulrich.weig...@de.ibm.com
