https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86850
--- Comment #2 from David Binderman <dcb314 at hotmail dot com> ---
Indeed it does look like vectorizer code. Here are 20 frames,
found by using the UBSAN_OPTIONS=print_stacktrace=1 option:
../../trunk/gcc/vec.h:1688:5: runtime error: member call on null pointer of
type
'struct vec'
#0 0x2be4a24 in vec<_slp_tree*, va_heap, vl_ptr>::splice(vec<_slp_tree*,
va_
heap, vl_ptr> const&) ../../trunk/gcc/vec.h:1688
#1 0x2be4a24 in vect_build_slp_tree_2 ../../trunk/gcc/tree-vect-slp.c:1492
#2 0x2bd779e in vect_build_slp_tree ../../trunk/gcc/tree-vect-slp.c:1105
#3 0x2bdba6c in vect_build_slp_tree_2 ../../trunk/gcc/tree-vect-slp.c:1257
#4 0x2bd779e in vect_build_slp_tree ../../trunk/gcc/tree-vect-slp.c:1105
#5 0x2bdba6c in vect_build_slp_tree_2 ../../trunk/gcc/tree-vect-slp.c:1257
#6 0x2bd779e in vect_build_slp_tree ../../trunk/gcc/tree-vect-slp.c:1105
#7 0x2bf1e80 in vect_analyze_slp_instance
../../trunk/gcc/tree-vect-slp.c:19
56
#8 0x2bfa002 in vect_analyze_slp(vec_info*, unsigned int)
../../trunk/gcc/tr
ee-vect-slp.c:2154
#9 0x2bfaf63 in vect_slp_analyze_bb_1 ../../trunk/gcc/tree-vect-slp.c:2839
#10 0x2bfaf63 in vect_slp_bb(basic_block_def*)
../../trunk/gcc/tree-vect-slp
.c:2973
#11 0x2c0d5bc in execute ../../trunk/gcc/tree-vectorizer.c:1271
#12 0x1b4e1ac in execute_one_pass(opt_pass*) ../../trunk/gcc/passes.c:2446
#13 0x1b51cf7 in execute_pass_list_1 ../../trunk/gcc/passes.c:2535
#14 0x1b51d3e in execute_pass_list_1 ../../trunk/gcc/passes.c:2536
#15 0x1b51d3e in execute_pass_list_1 ../../trunk/gcc/passes.c:2536
#16 0x1b51e18 in execute_pass_list(function*, opt_pass*)
../../trunk/gcc/pas
ses.c:2546
#17 0xc9d9da in cgraph_node::expand() ../../trunk/gcc/cgraphunit.c:2116
#18 0xca2db4 in expand_all_functions ../../trunk/gcc/cgraphunit.c:2254
#19 0xca2db4 in symbol_table::compile() ../../trunk/gcc/cgraphunit.c:2605
#20 0xcaca6a in symbol_table::finalize_compilation_unit()
../../trunk/gcc/cg
raphunit.c:2698
