Hi Thomas, If this looks like my fault I am happy to look into this and fix the bug if you can tell me how to reproduce it. I recently changed GET_MODE_INNER (m) to return 'm' itself if there is no inner mode and I thought I'd fixed up lto, but it seems I got it wrong. It also sounds like there is another bug in this area too - if I want to test this do I need to apply any other patches too?
Regards, David. > > Hi! > > It seems as if David's »[PATCH][1/N] Change GET_MODE_INNER to always > return a non-void mode« is relevant here: > > On Tue, 4 Aug 2015 16:06:23 +0300, Ilya Verbin <iver...@gmail.com> wrote: > > On Tue, Aug 04, 2015 at 14:35:11 +0200, Thomas Schwinge wrote: > > > On Fri, 31 Jul 2015 20:13:02 +0300, Ilya Verbin <iver...@gmail.com> wrote: > > > > On Fri, Jul 31, 2015 at 18:59:59 +0200, Jakub Jelinek wrote: > > > > > > > On Wed, Feb 18, 2015 at 11:00:35 +0100, Jakub Jelinek wrote: > > > > > > > + /* First search just the GET_CLASS_NARROWEST_MODE to wider > > > > > > > modes, > > > > > > > + if not found, fallback to all modes. */ > > > > > > > + int pass; > > > > > > > + for (pass = 0; pass < 2; pass++) > > > > > > > + for (machine_mode mr = pass ? VOIDmode > > > > > > > + : GET_CLASS_NARROWEST_MODE (mclass); > > > > > > > + pass ? mr < MAX_MACHINE_MODE : mr != VOIDmode; > > > > > > > + pass ? mr = (machine_mode) (m + 1) > > > > > > > + : mr = GET_MODE_WIDER_MODE (mr)) > > > > > > > + if (GET_MODE_CLASS (mr) != mclass > > > > > > > + || GET_MODE_SIZE (mr) != size > > > > > > > + || GET_MODE_PRECISION (mr) != prec > > > > > > > + || GET_MODE_INNER (mr) != inner > > > > > > > + || GET_MODE_IBIT (mr) != ibit > > > > > > > + || GET_MODE_FBIT (mr) != fbit > > > > > > > + || GET_MODE_NUNITS (mr) != nunits) > > > > > > > + continue; > > > > > > > > > > > > > > Given that gomp-4_1-branch works ok, the problem was introduced > > > > > > > somewhere > > > > > > > between 9 and 31 Jul. I'll try to find the revision. > > > > > > > > > > > > Shouldn't 'mr' be here instead of 'm'? > > > > > > > > > > I think so. If it works, patch preapproved. > > > > > > > > It fixes the infinite loop, but causes an error: > > > > lto1: fatal error: unsupported mode QI > > > > > > Confirmed. > > > > > > > > But wonder what changed that we haven't been triggering it before. > > > > > What mode do you think it on > > > > > (mclass/size/prec/inner/ibit/fbit/nunits)? > > > > > > > > When in hangs, mr is HImode. > > > > > > Do you already have any further analysis, a workaround, or even a fix? > > > > Not yet. I thought since Jakub is the author of this function, he could > > easily > > point what is wrong here :) Actually, intelmic doesn't require > > lto_input_mode_table, so temporary workaround is just to disable it. > > Well, avoiding lto_input_mode_table doesn't help us with nvptx > offloading... ;-) > > Anyway, I found that if I revert r226328, »[PATCH][1/N] Change > GET_MODE_INNER to always return a non-void mode«, > <https://gcc.gnu.org/ml/gcc-patches/2015-07/msg02350.html>, the problem > goes away. I'm trying, but I cannot claim yet to really understand this > mode streaming code... But, with the producer > gcc/lto-streamer-out.c:lto_write_mode_table having been changed, does > maybe the consumer gcc/lto-streamer-in.c:lto_input_mode_table also need > to be updated accordingly? > > For reference, David's change to > gcc/lto-streamer-out.c:lto_write_mode_table: > > @@ -2679,23 +2679,23 @@ lto_write_mode_table (void) > /* Ensure that for GET_MODE_INNER (m) != VOIDmode we have > also the inner mode marked. */ > for (int i = 0; i < (int) MAX_MACHINE_MODE; i++) > if (streamer_mode_table[i]) > { > machine_mode m = (machine_mode) i; > - if (GET_MODE_INNER (m) != VOIDmode) > + if (GET_MODE_INNER (m) != m) > streamer_mode_table[(int) GET_MODE_INNER (m)] = 1; > } > /* First stream modes that have GET_MODE_INNER (m) == VOIDmode, > so that we can refer to them afterwards. */ > for (int pass = 0; pass < 2; pass++) > for (int i = 0; i < (int) MAX_MACHINE_MODE; i++) > if (streamer_mode_table[i] && i != (int) VOIDmode && i != (int) > BLKmode) > { > machine_mode m = (machine_mode) i; > - if ((GET_MODE_INNER (m) == VOIDmode) ^ (pass == 0)) > + if ((GET_MODE_INNER (m) == m) ^ (pass == 0)) > continue; > bp_pack_value (&bp, m, 8); > bp_pack_enum (&bp, mode_class, MAX_MODE_CLASS, GET_MODE_CLASS (m)); > bp_pack_value (&bp, GET_MODE_SIZE (m), 8); > bp_pack_value (&bp, GET_MODE_PRECISION (m), 16); > bp_pack_value (&bp, GET_MODE_INNER (m), 8); > > (Also, the source code comments need to be updated?) > > > Grüße, > Thomas
