[Bug middle-end/64339] New: reject unsafe options in pragma GCC optimize

[manu at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64339

            Bug ID: 64339
           Summary: reject unsafe options in pragma GCC optimize
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: manu at gcc dot gnu.org

Some options are known to be unsafe to set via pragma GCC optimize. See:
https://sourceware.org/ml/libc-alpha/2014-12/msg00597.html and
https://sourceware.org/ml/libc-alpha/2014-12/msg00599.html

It would be better to add a flag to the *.opt files to mark safe options
explicitly, such that specifying any option that is not safe produces a fatal
error.