https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71153
--- Comment #6 from ktkachov at gcc dot gnu.org --- (In reply to ktkachov from comment #5) > In the foo_clear_bit_unlock case combine tries to match: > (parallel [ > (set (mem/v:DI (reg:DI 88) [-1 S8 A64]) > (unspec_volatile:DI [ > (and:DI (not:DI (reg:DI 85 [ mask ])) > (mem/v:DI (reg:DI 88) [-1 S8 A64])) > (const_int 3 [0x3]) > ] UNSPECV_ATOMIC_OP)) > (clobber (scratch:DI)) > ]) > > which are exactly the semantics of ldclrl but our patterns don't match that But adding a pattern for that to atomics.md doesn't work because the MEM rtx here is volatile and combine performs recog after initialising with init_recog_no_volatile (). Changing that call to just init_recog () in combine_instructions allows this to recognise (but is, of course, not the right way to do this)
