Ulrich Weigand wrote: > Georg-Johann Lay wrote: > >> Trying to make named address space support work for target AVR, >> I am facing the following problem: >> >> For generic AS, there are three valid base pointer registers >> X , Y and Z. >> >> For the new __pgm AS, only Z is available without offset. >> >> The problem is now that addresses.h:base_reg_class() does not >> pass down AS information, i.e. addr_space_t down to target hook >> MODE_CODE_BASE_REG_CLASS. >> >> Likewise for REGNO_MODE_CODE_OK_FOR_BASE_P. >> >> The MODE argument that both of these get describe the mode of >> the MEM but not the mode associated with the AS. >> >> Thus, it is not possible to provide proper implementations of >> these hooks. IRA/reload choses the wrong hard register so >> that in postreload no constraints match, i.e. >> TARGET_ADDR_SPACE_LEGITIMATE_ADDRESS_P returns wrong for that >> hard register (which is right) so that postreload busts. >> >> I'd just like to reassure me that I didn't do something fundamentally >> wrong and named address space support if not yet smoothly supported >> in GCC. > > No, you're correct. The only target supporting named address spaces > today is spu-elf, and here we're eliminating any reference to the > non-default space during expand, so that reload never sees any.
So a solution for me would be to expand as inline asm instead of as proper insns. Yes, it's hack. But before AS support I tried it via builtin that expanded as unspec and IRA created horribly bloated code. The annoyance is that only POST_INC addresses for one single hard reg is supported by the device. Greetings from spill fails... > This means that problems like the one you're seeing have been hidden > so far. I've started looking into fixing this, but since I don't > have a target where this is needed, this effort never really went > anywhere. I'll append below a patch I did a year or so ago; just > as something to look at, it probably will not even apply to the > current sources any more. Sounds great that you tried to fix it! Much work below... wow. > I'd be happy to bring this up to date if you're willing to work with > me to get this tested on a target that needs this support ... Just attached a patch to bugzilla because an AVR user wanted to play with the AS support and asked me to supply my changes. It's still in a mess but you could get a more reasonable base than on a target where all named addresses vanish at expand. The patch is fresh and attached to the enhancement PR49868, just BE stuff. There is also some sample code. http://gcc.gnu.org/PR49868 Johann > Bye, > Ulrich > > > > ChangeLog: > > * doc/tm.texi (MODE_CODE_BASE_REG_CLASS): Add address space > argument. > (REGNO_MODE_CODE_OK_FOR_BASE_P): Likewise. > > * config/cris/cris.h (MODE_CODE_BASE_REG_CLASS): Add address > space argument. > (REGNO_MODE_CODE_OK_FOR_BASE_P): Likewise. > * config/bfin/bfin.h (MODE_CODE_BASE_REG_CLASS): Likewise. > (REGNO_MODE_CODE_OK_FOR_BASE_P): Likewise. > > * addresses.h (base_reg_class): Add address space argument. > Pass to MODE_CODE_BASE_REG_CLASS. > (ok_for_base_p_1): Add address space argument. Pass to > REGNO_MODE_CODE_OK_FOR_BASE_P. > (regno_ok_for_base_p): Add address space argument. Pass to > ok_for_base_p_1. > > * regrename.c (scan_rtx_address): Add address space argument. > Pass address space to regno_ok_for_base_p and base_reg_class. > Update recursive calls. > (scan_rtx): Pass address space to scan_rtx_address. > (build_def_use): Likewise. > * regcprop.c (replace_oldest_value_addr): Add address space > argument. Pass to regno_ok_for_base_p and base_reg_class. > Update recursive calls. > (replace_oldest_value_mem): Pass address space to > replace_oldest_value_addr. > (copyprop_hardreg_forward_1): Likewise. > > * reload.c (find_reloads_address_1): Add address space argument. > Pass address space to base_reg_class and regno_ok_for_base_p. > Update recursive calls. > (find_reloads_address): Pass address space to base_reg_class, > regno_ok_for_base_p, and find_reloads_address_1. > (find_reloads): Pass address space to base_reg_class. > (find_reloads_subreg_address): Likewise. > > * ira-costs.c (record_reg_classes): Update calls to base_reg_class. > (ok_for_base_p_nonstrict): Add address space argument. Pass to > ok_for_base_p_1. > (record_address_regs): Add address space argument. Pass to > base_reg_class and ok_for_base_p_nonstrict. Update recursive calls. > (record_operand_costs): Pass address space to record_address_regs. > (scan_one_insn): Likewise. > > * caller-save.c (init_caller_save): Update call to base_reg_class. > * ira-conflicts.c (ira_build_conflicts): Likewise. > * reload1.c (maybe_fix_stack_asms): Likewise.
