2012/3/19 Georg-Johann Lay <a...@gjlay.de>: > http://gcc.gnu.org/ml/gcc-patches/2012-03/msg00641.html > > Georg-Johann Lay wrote: >> The problem with the PR is that lower-subreg.c happily splits multi-byte >> moves >> from address spaces without knowing anything about the additional costs this >> is >> causing. >> >> The TARGET_MODE_DEPENDENT_ADDRESS_P hook cannot be used for 16-bit addresses >> because that hook is not sensitive to address spaces, but is is used for the >> 24-bit address space to avoid subreg lowering for PSImode. >> >> For the 16-bit address spaces the mov expander now assigns the address >> register >> by hand as post-increment. >> >> Luckily, post-increment is the only addressing mode that makes sense with the >> non-generic address spaces and there is no choice for the address register >> resp. addressing mode, anyway... >> >> This patch does not fix the PR issue, of course, it just avoids subreg >> lowering >> by using/pretending mode-dependent addresses. >> >> Ok for trunk? >> >> Johann >> >> PR rtl-optimization/52543 >> * config/avr/avr.c (avr_mode_dependent_address_p): New function. >> (TARGET_MODE_DEPENDENT_ADDRESS_P): New define. >> >> * config/avr/avr.md (unspec): Add UNSPEC_LPM. >> (load_<mode>_libgcc): Use UNSPEC_LPM instead of MEM. >> (mov<mode>): For multi-byte move from non-generic >> 16-bit address spaces: Expand to use Z++ as address for >> inline code and use UNSPEC_LPM (Z) for code from libgcc. >> (load<mode>_libgcc): Remove expander. >> (split-lpmx): Remove split. >
Approved. Denis.
