https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92945
--- Comment #2 from Sergei Trofimovich <slyfox at inbox dot ru> ---
Rebuilt isl with debugging symbols. gdb says 'bmap' is NULL:
Thread 2.1 "f951" received signal SIGSEGV, Segmentation fault.
[Switching to process 1944963]
isl_basic_map_underlying_set (bmap=0x0) at ../isl-0.22/isl_map.c:5515
5515 space = isl_space_underlying(space, bmap->n_div);
(gdb) bt
#0 isl_basic_map_underlying_set (bmap=0x0) at ../isl-0.22/isl_map.c:5515
#1 0x00007ffff7e56431 in isl_basic_map_is_empty (bmap=0x28185f0) at
../isl-0.22/isl_map.c:8988
#2 isl_basic_map_is_empty (bmap=0x28185f0) at ../isl-0.22/isl_map.c:8958
#3 0x00007ffff7e578da in map_product (map1=0x27eb7b0, map2=0x27f4a90,
space_product=<optimized out>,
basic_map_product=0x7ffff7e4dfa0 <isl_basic_map_range_product>,
remove_duplicates=1) at ../isl-0.22/isl_map.c:10468
#4 0x00007ffff7e2ede3 in coscheduled_source (acc=acc@entry=0x27f8c20,
old_map=0x27f4a90, pos=pos@entry=8, depth=<optimized out>) at
../isl-0.22/isl_flow.c:941
#5 0x00007ffff7e3115c in handle_coscheduled (flow=0x28455d0,
may_rel=0x2845370, must_rel=0x2845330, acc=0x27f8c20) at
../isl-0.22/isl_flow.c:1034
#6 compute_val_based_dependences (acc=<optimized out>) at
../isl-0.22/isl_flow.c:1238
#7 access_info_compute_flow_core (acc=<optimized out>, acc@entry=0x27f8c20) at
../isl-0.22/isl_flow.c:1338
#8 0x00007ffff7e326ac in compute_single_flow (data=0x7fffffffcfc0,
sink=<optimized out>, uf=0x27d6410) at ../isl-0.22/isl_flow.c:3082
#9 compute_flow_schedule (access=0x28ab6e0) at ../isl-0.22/isl_flow.c:3166
#10 isl_union_access_info_compute_flow (access=0x28ab6e0) at
../isl-0.22/isl_flow.c:3217
#11 0x00000000017b5b9e in scop_get_dependences(scop*) ()
#12 0x00000000017b603b in apply_poly_transforms(scop*) ()
#13 0x00000000017b02d2 in graphite_transform_loops() ()
#14 0x00000000017b0809 in (anonymous
namespace)::pass_graphite_transforms::execute(function*) ()
#15 0x0000000000c0caed in execute_one_pass(opt_pass*) ()
#16 0x0000000000c0d50f in execute_pass_list_1(opt_pass*) ()
#17 0x0000000000c0d521 in execute_pass_list_1(opt_pass*) ()
#18 0x0000000000c0d521 in execute_pass_list_1(opt_pass*) ()
#19 0x0000000000c0d521 in execute_pass_list_1(opt_pass*) ()
#20 0x0000000000c0d53a in execute_pass_list(function*, opt_pass*) ()
#21 0x000000000080d779 in cgraph_node::expand() ()
#22 0x000000000080f2c2 in symbol_table::compile() ()
#23 0x00000000008117ba in symbol_table::finalize_compilation_unit() ()
#24 0x0000000000cfab26 in compile_file() ()
#25 0x0000000000cfd784 in toplev::main(int, char**) ()
#26 0x00000000018f083c in main ()
(gdb) list
5510 !isl_space_is_named_or_nested(bmap->dim, isl_dim_in) &&
5511 !isl_space_is_named_or_nested(bmap->dim, isl_dim_out))
5512 return bset_from_bmap(bmap);
5513 bmap = isl_basic_map_cow(bmap);
5514 space = isl_basic_map_take_space(bmap);
5515 space = isl_space_underlying(space, bmap->n_div);
5516 bmap = isl_basic_map_restore_space(bmap, space);
5517 if (!bmap)
5518 return NULL;
5519 bmap->extra -= bmap->n_div;
(gdb) print bmap
$1 = (isl_basic_map *) 0x0
