[Bug libgcc/71951] New: libgcc_s built with -fomit-frame-pointer on aarch64 is broken

[timo.teras at iki dot fi]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71951

            Bug ID: 71951
           Summary: libgcc_s built with -fomit-frame-pointer on aarch64 is
                    broken
           Product: gcc
           Version: 6.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libgcc
          Assignee: unassigned at gcc dot gnu.org
          Reporter: timo.teras at iki dot fi
  Target Milestone: ---

On gcc 6.1.0 if CFLAGS contains -fomit-frame-pointer it is used to build
libgcc_s. On Aarch64 this creates non-working libgcc_s and it crashes when
unwinding.

I suppose the unwinding code needs frame pointers always. This probably worked
until https://gcc.gnu.org/ml/gcc-patches/2013-03/msg01228.html made
omit-frame-pointer skip it for leaf functions. I guess the unwinding leaf
functions should have attributes for no-omit-frame-pointer, or just add
-fno-omit-frame-pointer for the relevant files.