trippels@gcc2-power8 generic % cat nsLineLayout.ii
enum class A { foo };
void fn1(const A test) {
  switch (test)
  case A::foo: ;
}

trippels@gcc2-power8 generic % g++ -c nsLineLayout.ii
nsLineLayout.ii: In function ‘void fn1(A)’:
nsLineLayout.ii:4:11: internal compiler error: tree check: expected integer_cst, have nop_expr in get_val, at tree.h:5157
   case A::foo: ;
           ^~~

0x10d9ee93 tree_check_failed(tree_node const*, char const*, int, char const*, ...)
        ../../gcc/gcc/tree.c:9587
0x10120d9b tree_int_cst_elt_check
        ../../gcc/gcc/tree.h:3144
0x104a9c8f tree_int_cst_elt_check
        ../../gcc/gcc/tree.h:3147
0x104a9c8f wi::extended_tree<192>::get_val() const
        ../../gcc/gcc/tree.h:5157
0x104a9c8f wi::int_traits<generic_wide_int<wi::extended_tree<192> > >::decompose(long*, unsigned int, generic_wide_int<wi::extended_tree<192> > const&)
        ../../gcc/gcc/wide-int.h:898
0x104a9c8f wide_int_ref_storage<generic_wide_int<wi::extended_tree<192> > >
        ../../gcc/gcc/wide-int.h:945
0x104a9c8f generic_wide_int<generic_wide_int<wi::extended_tree<192> > >
        ../../gcc/gcc/wide-int.h:722
0x104a9c8f lts_p<generic_wide_int<wi::extended_tree<192> >, generic_wide_int<wi::extended_tree<192> > >
        ../../gcc/gcc/wide-int.h:1749
0x104a9c8f tree_int_cst_lt
        ../../gcc/gcc/tree.h:5217
0x104a9c8f c_add_case_label(unsigned int, splay_tree_s*, tree_node*, tree_node*, tree_node*, tree_node*, bool*)
        ../../gcc/gcc/c-family/c-common.c:6592
0x1019f217 finish_case_label(unsigned int, tree_node*, tree_node*)
        ../../gcc/gcc/cp/decl.c:3417
0x102fb753 cp_parser_label_for_labeled_statement
        ../../gcc/gcc/cp/parser.c:10259
0x102e4ca3 cp_parser_statement
        ../../gcc/gcc/cp/parser.c:10132
0x1031e23b cp_parser_implicitly_scoped_statement
        ../../gcc/gcc/cp/parser.c:11557
0x102e56d3 cp_parser_selection_statement
        ../../gcc/gcc/cp/parser.c:10632
0x102e56d3 cp_parser_statement
        ../../gcc/gcc/cp/parser.c:10040
0x102e6617 cp_parser_statement_seq_opt
        ../../gcc/gcc/cp/parser.c:10456
0x102e67ef cp_parser_compound_statement
        ../../gcc/gcc/cp/parser.c:10410
0x1031325b cp_parser_function_body
        ../../gcc/gcc/cp/parser.c:20225
0x1031325b cp_parser_ctor_initializer_opt_and_function_body
        ../../gcc/gcc/cp/parser.c:20261