[Bug other/98027] New: CET support is documented to be explicitly enabled, however it's enabled by default

[doko at debian dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98027

            Bug ID: 98027
           Summary: CET support is documented to be explicitly enabled,
                    however it's enabled by default
           Product: gcc
           Version: 10.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: doko at debian dot org
  Target Milestone: ---

CET support is documented to be explicitly enabled, however it's enabled by
default.

install.texi reads:

@item --enable-cet
@itemx --disable-cet
Enable building target run-time libraries with control-flow
instrumentation, see @option{-fcf-protection} option.  When
@code{--enable-cet} is specified target libraries are configured
to add @option{-fcf-protection} and, if needed, other target
specific options to a set of building options.

The option is disabled by default.  When @code{--enable-cet=auto}
is used, it is enabled on Linux/x86 if target binutils
supports @code{Intel CET} instructions and disabled otherwise.
In this case the target libraries are configured to get additional
@option{-fcf-protection} option.

however it's still enabled when no --enable-/--disable-cet configure options is
given.

Please either update the documentation or the behavior. Seems to be the case
for the gcc-10 branch as well.

unreleated question: when do you configure with -fcf-protection -mshstk, and
when just with -fcf-protection?