2011/6/28 Ian Lance Taylor <iant@xxxxxxxxxx>: > Aurelien Buhrig <aurelien.buhrig.gcc@xxxxxxxxx> writes: > >> I'm trying to implement TARGET_SECONDARY_RELOAD but I cannot make it >> work properly. >> The hook seems to work for preventing from moving from BASE_REG to >> BASE_REG in HImode by inserting a GENERAL_REG. >> But I also want to insert a GENERAL_REGS intermediate register when >> moving between BASE_REGS registers and memory in HImode. >> >> So I wrote something like that in my TARGET_SECONDARY_RELOAD: >> if (MEM_P(x) && (reload_mode == HImode) && reload_class == BASE_REGS) >> return GENERAL_REGS; >> >> >> But it seems this do not work. For instance with DI function parameter >> access (movdi reg:DI <-- m) which are (automatically) split into movhi >> subreg:HI <-- m; then in movhi reg:HI <- m. But the hook do not seem >> to work since the reg:HI is reloaded into a BASE_REG... >> >> So when is this hook called? Is there something specific with spliting >> insn? Or just a general thing about TARGET_SECONDARY_RELOAD I missed ? > > The hook is called during reload, which is run as part of register > allocation. When are you splitting the DImode load? > > Ian > I have no instruction for it. GCC automatically splits it, and it does it at the very beginning (131r.expand) by affecting a subreg:HI, and affects a reg:HI at 139r.subregs, and a hard base_reg at 176r.greg. It is never changed after. Would it be a reg class pb ? For now, I defined BASE_REGS class for address registers which does not intersect with GENERAL_REGS class (the data registers). Should I define Address register and data register as general register, with a class for address register and a new class for data registers (such as m68k) ? Does GCC treat GENERALS_REGS differently than other classes ? Aurélien
