[Bug debug/84550] [8 Regression] stepping through gcc does not work with gdb 8.0.1

["palves at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84550

--- Comment #4 from Pedro Alves <palves at redhat dot com> ---
~~~~~~~~~~~~
    infrun: stepped into subroutine
#1  infrun: inserting step-resume breakpoint at 0x5b88b8
#2  infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current
thread [process 25164] at 0x853b60
    infrun: prepare_to_wait
    infrun: target_wait (-1.0.0, status) =
    infrun:   -1.0.0 [process -1],
    infrun:   status->kind = ignore
    infrun: TARGET_WAITKIND_IGNORE
    infrun: prepare_to_wait
    a.f90:8:0:
~~~~~~~~~~~~

The #1 above is GDB placing a breakpoint after the prologue of the subroutine,
to skip the prologue and stop at the first line of user code.  The #2 above is
GDB continuing the thread until it hits that internal breakpoint.  But it looks
like the breakpoint isn't ever hit?

It sounds like the end-of-prologue address might be incorrect.   0x5b88b8 seems
too off from 0x853b60.  Should usually be an address close and higher than
0x853b60.