[Bug c++/70613] New: -fabi-version docs don't match implementation

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70613

            Bug ID: 70613
           Summary: -fabi-version docs don't match implementation
           Product: gcc
           Version: 5.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: wilson at gcc dot gnu.org
  Target Milestone: ---

In docs/invoke.texi, it says that 8 is the highest value for -fabi-version.  In
c-family/c-opts.c, flag_abi_version gets set to 9.  I see two places that check
for abi_version of 9 in cp/class.c.  And one place in cp/decl.c.

At first glance it appears that this is just a documentation bug.  I haven't
verified this yet.

Since gcc-5 is the first version that defaults to -fabi-version=0, we really
should get the -fabi-version docs correct.