https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100734
--- Comment #5 from John David Anglin <danglin at gcc dot gnu.org> ---
Breakpoint 1, attr_access::from_mode_char (
c=<error reading variable: Cannot access memory at address 0x0>)
at ../../gcc/gcc/attribs.h:304
304 gcc_unreachable ();
(gdb) bt
#0 attr_access::from_mode_char (
c=<error reading variable: Cannot access memory at address 0x0>)
at ../../gcc/gcc/attribs.h:304
#1 0x4000000000a8311c in init_attr_rdwr_indices (rwm=0x800003fffdff14e0,
attrs=0x800003fffdf1b9b0) at ../../gcc/gcc/attribs.c:2146
#2 0x4000000000d1e554 in warn_parm_array_mismatch (origloc=2147484671,
fndecl=0x800003fffdf1b9b0, newparms=0x7ae4b8)
at ../../gcc/gcc/c-family/c-warn.c:3369
#3 0x4000000000b5ebc0 in c_parser_declaration_or_fndef (
parser=0x800003fffdff14e0, fndef_ok=128, static_assert_ok=false,
empty_ok=true, nested=false, start_attr_ok=false,
objc_foreach_object_declaration=0x4000000000887f48
<copy_list(tree_node*)::__FUNCTION__>, omp_declare_simd_clauses=...,
have_attrs=false,
attrs=0x800003fffdf1d700,
oacc_routine_data=0x4000000002f7501f <fndecl_built_in_p(tree_node
const*)+92>, fallthru_attr_p=0x800003fffdff17a0) at
../../gcc/gcc/c/c-parser.c:2342
#4 0x4000000000b5cb98 in c_parser_external_declaration (
parser=0x800003fffdff14e0) at ../../gcc/gcc/c/c-parser.c:1777
#5 0x4000000000b5c240 in c_parser_translation_unit (parser=0x800003fffdff14e0)
at ../../gcc/gcc/c/c-parser.c:1650
#6 0x4000000000bc644c in c_parse_file () at ../../gcc/gcc/c/c-parser.c:21994
#7 0x4000000000cafd10 in c_common_parse_file ()
at ../../gcc/gcc/c-family/c-opts.c:1219
#8 0x40000000017db87c in compile_file () at ../../gcc/gcc/toplev.c:457
#9 0x40000000017e26e8 in do_compile () at ../../gcc/gcc/toplev.c:2203
#10 0x40000000017e2e68 in toplev::main (this=0x800003fffdff14e0,
argc=-2147482625, argv=0x7ae4b8) at ../../gcc/gcc/toplev.c:2342
#11 0x4000000002abbee4 in main (argc=-2147482625, argv=0x800003fffdf1b9b0)
at ../../gcc/gcc/main.c:39
(gdb) frame 1
#1 0x4000000000a8311c in init_attr_rdwr_indices (rwm=0x800003fffdff14e0,
attrs=0x800003fffdf1b9b0) at ../../gcc/gcc/attribs.c:2146
2146 acc.mode = acc.from_mode_char (*m);
(gdb) p *m
$2 = 0 '\000'
