With simple program, foo.f:
[begin literal]
      program foo
      implicit none
      logical*4 e
      e = .true.
      stop
      end
[end literal]

I get these results:

$ /usr/bin/gfortran    -g foo.f -o foo

harryr@HARRYR-PC ~
$ gdb
GNU gdb (GDB) (Cygwin 7.10.1-1) 7.10.1
Copyright (C) 2015 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
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There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i686-pc-cygwin".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
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(gdb) file foo
Reading symbols from foo...done.
(gdb) tb foo.f:1
Temporary breakpoint 1 at 0x4011d6: file foo.f, line 1.
(gdb) r
Starting program: /cygdrive/c/Users/harryr/foo
[New Thread 8148.0x1fd8]
[New Thread 8148.0x1d24]
gdb: unknown target exception 0x406d1388 at 0x759cc54f

Program received signal ?, Unknown signal.
0x759cc54f in RaiseException ()
   from /cygdrive/c/Windows/syswow64/KERNELBASE.dll
(gdb)

Please help.