[Bug fortran/61073] New: -fcheck='do' leads to twice the amount of GDB steps in a do loop

["sarantis.pantazis at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=61073

            Bug ID: 61073
           Summary: -fcheck='do' leads to twice the amount of GDB steps in
                    a do loop
           Product: gcc
           Version: 4.8.2
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sarantis.pantazis at gmail dot com

I am not sure if this is a bug or the way it is supposed to work, but I could
not find anything relative online. I have written the following code:

##################################
PROGRAM test
implicit none

integer::i

do i=1,3
    write(*,*) 'bla'
end do

end program
##################################

If I compile with "gfortran -o bla test.f90 -fcheck='do' -g", the steps of
debugging through GDB show that lines 6-7 are accessed six times instead of
three.

##################################

Breakpoint 1, test () at test.f90:6
6    do i=1,3
(gdb) step
7        write(*,*) 'bla'
(gdb) 
 bla
6    do i=1,3
(gdb) 
7        write(*,*) 'bla'
(gdb) 
6    do i=1,3
(gdb) 
7        write(*,*) 'bla'
(gdb) 
 bla
6    do i=1,3
(gdb) 
7        write(*,*) 'bla'
(gdb) 
6    do i=1,3
(gdb) 
7        write(*,*) 'bla'
(gdb) 
 bla
6    do i=1,3
(gdb) 
7        write(*,*) 'bla'
(gdb) 
6    do i=1,3
(gdb) 
10    end program
(gdb) 

##################################

The output of gfortran -v:

Using built-in specs.
COLLECT_GCC=gfortran
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.8/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.8.2-19ubuntu1'
--with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs
--enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.8 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls
--with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libmudflap
--enable-plugin --with-system-zlib --disable-browser-plugin
--enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-amd64
--with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686
--with-abi=m64 --with-multilib-list=m32,m64,mx32 --with-tune=generic
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1)