On Mon, Nov 4, 2019 at 4:30 PM Richard Sandiford <richard.sandif...@arm.com> wrote: > > With a later patch I saw a case in which we peeled a single iteration > for gaps but didn't need to peel further iterations to make up a full > vector. We then tried to vectorise the single-iteration epilogue.
But when peeling for gaps we peel off a full vector iteration and thus have possibly VF-1 iterations in the epilogue, enough for vectorizing with VF/2? > > 2019-11-04 Richard Sandiford <richard.sandif...@arm.com> > > gcc/ > * tree-vect-loop.c (vect_analyze_loop): Only try to vectorize > the epilogue if there are peeled iterations for it to handle. > > Index: gcc/tree-vect-loop.c > =================================================================== > --- gcc/tree-vect-loop.c 2019-11-04 15:18:26.684592505 +0000 > +++ gcc/tree-vect-loop.c 2019-11-04 15:18:36.608524542 +0000 > @@ -2462,6 +2462,7 @@ vect_analyze_loop (class loop *loop, loo > vect_epilogues = (!loop->simdlen > && loop->inner == NULL > && PARAM_VALUE (PARAM_VECT_EPILOGUES_NOMASK) > + && LOOP_VINFO_PEELING_FOR_NITER (first_loop_vinfo) > /* For now only allow one epilogue loop. */ > && first_loop_vinfo->epilogue_vinfos.is_empty ()); >
