On April 12, 2018 5:38:44 PM GMT+02:00, Jakub Jelinek <ja...@redhat.com> wrote: >On Thu, Apr 12, 2018 at 05:17:29PM +0200, Richard Biener wrote: >> >For -Os that is easily measurable regression, for -O2 it depends on >the >> >relative speed of memcpy vs. mempcpy and whether one or both of them >> >are in >> >I-cache or not. >> >> Well, then simply unconditionally not generate a libcall from the >move expander? > >We need to generate libcall for many callers and in fact, we don't have >a >mode nor a way to tell the caller that we haven't emitted anything. > >What we could do is add another enumerator to enum block_op_methods >that >would be like BLOCK_OP_NO_LIBCALL, but would not use >emit_block_move_via_loop >if move_by_pieces nor emit_block_move_via_movmem can be used, and say >instead return const0_rtx or pc_rtx or some way to tell the caller that >it hasn't emitted anything and in expand_builtin_memory_copy_args >pass for endp == 1 && target != const0_rtx that new >BLOCK_OP_NO_LIBCALL_LOOP >to emit_block_move_hints and return 0 if dest_addr is const0_rtx (or >pc_rtx >or whatever is chosen).
Yes. Emit the "original" call whenever inline expansion fails. Richard. > Jakub
