https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96354
--- Comment #8 from rguenther at suse dot de <rguenther at suse dot de> --- On July 28, 2020 4:45:59 PM GMT+02:00, "jakub at gcc dot gnu.org" <gcc-bugzi...@gcc.gnu.org> wrote: >https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96354 > >--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> --- >So we have: > # DEBUG this => &<retval> > <retval> ={v} {CLOBBER}; > # DEBUG D#1 => &<retval>.d > # DEBUG D#2 => MEM[(double *)&<retval>] > # DEBUG __trans_tmp_3 => D#2 >in matmul during inlining, and inline it as: > # DEBUG this => &D.2697[_13] > _24 = &D.2697[_13]; > *_24 ={v} {CLOBBER}; > # DEBUG D#1 => &D.2697[_13].d > # DEBUG D#2 => MEM[(double *)&D.2697[_13]] > # DEBUG __trans_tmp_3 => D#2 > # DEBUG this => NULL >Generally, we are more lax about IL restrictions we have in debug stmts >compared to other stmts, e.g. verify_gimple_debug always returns false. >So, do we want to allow this case? >I believe cfgexpand.c handles that: > case MEM_REF: > if (!is_gimple_mem_ref_addr (TREE_OPERAND (exp, 0))) > { > tree newexp = fold_binary (MEM_REF, TREE_TYPE (exp), > TREE_OPERAND (exp, 0), > TREE_OPERAND (exp, 1)); > if (newexp) > return expand_debug_expr (newexp); > } > /* FALLTHROUGH */ > case INDIRECT_REF: >or punts if the folding doesn't come up with anything. >So, we could e.g. add bool is_debug argument to >maybe_canonicalize_mem_ref_addr, pass true only when in GIMPLE_DEBUG >and >instead of failing the assertion there return false (what about the >other >assertions in there?). >Or instead of bool is_debug take bool *is_debug and if non-NULL (only >for >GIMPLE_DEBUG) set it to *false if we'd otherwise fail and tell that way >to the >caller that it should reset the debug stmt? >richi, your thoughts on this? We could allow this in debug stmts but pretty much any (or very many) workers on MEM_REFs will be quite unhappy about this. Of course we're not likely to run them on debug stmts. But then, we do have debug Temps for this...
