Ian Lance Taylor wrote: > Jean Christophe Beyler <jean.christophe.bey...@gmail.com> writes: > >> All of these have an outer code of SET. Therefore, I'm not quite >> positive of how I'm supposed to implement my rtx_cost function. Since >> I don't seem to get a choice between a set 0xcb03 and a (plus 0xcafe >> 5), how can I tell the compiler the different costs? > > Make the CONST_INT more expensive than the PLUS. > > But I don't know that gcc will implement the particular optimization > that you are looking for. I'm not aware of any other processor which is > able to load a large constant in a single instruction, but for which an > add instruction is cheaper if there is a similar constant already > available. You may need to implement this as a peephole or as a machine > specific pass.
Take a look at reload_cse_move2add. Bernd -- This footer brought to you by insane German lawmakers. Analog Devices GmbH Wilhelm-Wagenfeld-Str. 6 80807 Muenchen Sitz der Gesellschaft Muenchen, Registergericht Muenchen HRB 40368 Geschaeftsfuehrer Thomas Wessel, William A. Martin, Margaret Seif