https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88958
--- Comment #1 from G. Steinmetz <gs...@t-online.de> ---
$ gdc-9-20190120 -c z1.d -O0
$
$ gdc-9-20190120 -c z1.d -O1
during GIMPLE pass: fre
In function 'h':
d21: internal compiler error: in copy_reference_ops_from_ref, at
tree-ssa-sccvn.c:976
0xce83a5 copy_reference_ops_from_ref
../../gcc/tree-ssa-sccvn.c:976
0xce90a5 valueize_shared_reference_ops_from_ref
../../gcc/tree-ssa-sccvn.c:1626
0xcea5a9 vn_reference_lookup(tree_node*, tree_node*, vn_lookup_kind,
vn_reference_s**, bool)
../../gcc/tree-ssa-sccvn.c:2708
0xcf16f9 visit_reference_op_load
../../gcc/tree-ssa-sccvn.c:4067
0xcf16f9 visit_stmt
../../gcc/tree-ssa-sccvn.c:4485
0xcf2aeb process_bb
../../gcc/tree-ssa-sccvn.c:6055
0xcf3eff do_rpo_vn
../../gcc/tree-ssa-sccvn.c:6662
0xcf4e2c execute
../../gcc/tree-ssa-sccvn.c:6797
