Vladimir Makarov <vmaka...@redhat.com> wrote: >> * lra.c (lra_update_insn_regno_info): Take account of arguments >> via memory which could be implicit usage of pseudo regs. >> > > It could be a solution but I believe the problem should be solved in > some other way. The patch will generate a correct code but it might > also generate worse code. The regs mentioned in insn data are always > processed for liveness and adding the pseudo can make live range > longer potentially worsening allocation of other pseudos. > > So I guess we need to find another solution for the problem. I > suspect spill_hard_reg is undefined as the pseudo 699 is present only > in CALL_INSN_USAGE. Otherwise, spill_hard_reg would be NULL. A > solution would be to figure out why there is only one reference, what > does it mean, and what we expect at the end of RA instead of pseudo > (e.g. anything, const or some register). And add code correspondingly > in remove_pseudos for case nrefs==0 or scratch pseudo (cases when > spill_hard_reg is not initialized). May be such code is the result of > wrong transformations (e.g. incomplete reg equiv substitution chain), > then it should be fixed somewhere else. > > It would be nice to have a small test case for this problem with > compiler options to reproduce it.
Thanks for the detailed explanation. The original issue has found with the older sh-lra branch which was based on trunk at this September. Now I've found that the original test case in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55212#c47 doesn't fail anymore on the current sh-lra branch without this patch. I withdraw it and will see if some other test fails without it. Regards, kaz
