Denis Chertykov schrieb:
Georg-Johann Lay:
PR52543 required to represent a load from non-generic address spaces as UNSPEC
instead of as MEM to avoid a gross code bloat.
http://gcc.gnu.org/PR52543
lower-subreg's cost model is still broken: It assumes that any loads from MEM
are from the generic address space and does not care for address spaces in its
cost model.
This patch undoes the changes from SVN r185605
http://gcc.gnu.org/viewcvs?view=revision&revision=185605
and installs a different but less intrusive hack around PR52543:
targetm.mode_dependent_address_p has an address space parameter so that the
backend can pretend all non-generic addresses are mode-dependent.
This keeps lower-subreg.c from splitting the loads, and it is possible to
represent the loads as MEM and there is no more the need to represent them as
UNSPECs.
This patch is still not an optimal solution but the code is much closer to a
clean solution now.
Ok for trunk?
You can apply it.
Denis.
I also applied the following change:
http://gcc.gnu.org/viewcvs?view=revision&revision=191825
* config/avr/avr.md (adjust_len): Add lpm.
(reload_in<mode>): Use avr_out_lpm for output. Use "lpm" for
adjust_len.
* config/avr/avr-protos.h (avr_out_lpm): New prototype.
* config/avr/avr.c (avr_out_lpm): Make global.
(adjust_insn_length): Handle ADJUST_LEN_LPM.
The reload_in<mode> insns used the wrong output functions.
Notice that this change is just a cosmetic change because the secondary
reload for the non-generic spaces are ignored. That is: despite
avr_secondary_reload, REG <- MEM input reloads are not mapped to their
secondary reload insn and the mov insn for that load is used.
This leads to a situation where the insn output function is not supplied
with the needed clobber register, thus the avr_find_unused_d_reg
function is needed to work around that.
Sigh. Even more FIXMEs in the avr backend...
Denis, do you know why the secondary reloads requested by
avr_secondary_reload are ignored? I see calls to this hook and
sri->icode is set to the right insn code but ignored afterwards.
The only calls to that hook with the right operands are from ira cost
computation.
From the internals I don't see why it is skipped and the responsiveness
in the gcc-help@ list on such topics is zero :-(
A test case is
$ avr-gcc -mmcu=atmega128 -S -std=gnu99 ...
int read (const __flash1 int *p)
{
return *p;
}
Johann
