[Bug debug/44113] New: bad

["andi-gcc at firstfloor dot org" <gcc-bugzilla at gcc dot gnu dot org>]

With gdb 7.1 / gcc 4.5.0 I noticed that unrolled loops have very poor
debugging information. The body cannot be single stepped, but a "next"
in gdb jumps over the whole iteration space.

For example:

main()
{
        int i;
        for (i = 0; i < 10; i++)
                printf("%d\n",i );
}

compiled with -O3 -g (which results in auto unrolling) gives:

(gdb) b main
Breakpoint 1 at 0x400520: file tloop2.c, line 2.
(gdb) r
Starting program: /home2/andi/tsrc/tloop2 

Breakpoint 1, main () at tloop2.c:2
2       {
(gdb) n
5                       printf("%d\n",i );
(gdb) n
0
1
2
3
4
5
6
7
8
6       }
(gdb) 

Note the single next stepped over the complete loop execution.
I would have expected next to only execute one iteration.

Is this a problem of the loop unroller not describing the unrolled
loop to the debugger?


-- 
           Summary: bad
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: andi-gcc at firstfloor dot org
  GCC host triplet: x86_64-linux
GCC target triplet: x86_64-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44113