[Bug debug/79342] New: [6 Regression] ICE in output_index_string, at dwarf2out.c:25635 with -gsplit-dwarf

["doko at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79342

            Bug ID: 79342
           Summary: [6 Regression] ICE in output_index_string, at
                    dwarf2out.c:25635 with -gsplit-dwarf
           Product: gcc
           Version: 6.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
          Assignee: unassigned at gcc dot gnu.org
          Reporter: doko at gcc dot gnu.org
  Target Milestone: ---

Created attachment 40651
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40651&action=edit
reduced file

seen on the gcc-6-branch, at least 20161005 and 20170202, not on 5 and on the
trunk.  May be related to PR70578.

$ g++-6 -std=gnu++11 -c -gsplit-dwarf -g3 -Og -fno-exceptions uvectr64.ii
uvectr64.ii:3031:1: internal compiler error: in output_index_string, at
dwarf2out.c:25635
 }
 ^
Please submit a full bug report,
with preprocessed source if appropriate.