It seems that combining -g3 and -gsplit-dwarf is the root cause for MY
problem.
Even gcc experiences an ICE.
/usr/bin/gcc-5 -std=gnu99 -o vp9_dsubexp.o -c -DNDEBUG=1 -DTRIMMED=1
-DHAVE_CONFIG_H=vpx_config.h -fPIC -DMOZILLA_CLIENT
-fno-builtin-strlen -Wl,--gdb-index -Dfdatasync=fdatasync
-DDEBUG_4GB_CHECK -DUSEHELGRIND=1 -gsplit-dwarf -g3 -Og
./vp9_dsubexp.i
/new-hd1/extra/ishikawa/TB-3HG/NEW-COMMSRC/mozilla/media/libvpx/libvpx/vp9/decoder/vp9_dsubexp.c:72:1:
internal compiler error: in output_index_string, at dwarf2out.c:22895
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-5/README.Bugs> for instructions.
ishikawa@ip030:/tmp$
Please see my followups to
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70578
TIA