[Bug debug/95360] inconsistent behaviors at -O0

["yangyibiao at hust dot edu.cn" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95360

--- Comment #5 from Yibiao Yang <yangyibiao at hust dot edu.cn> ---
(In reply to Tom de Vries from comment #3)
> (In reply to Yibiao Yang from comment #0)
> > Breakpoint 1, main () at small.c:5
> > 5	  for (; d<1; d++)
> > (gdb) stepi
> > 0x0000000000401154	5	  for (; d<1; d++)
> > (gdb) stepi
> > 0x000000000040115a	5	  for (; d<1; d++)
> > (gdb) stepi
> > 0x000000000040115c	5	  for (; d<1; d++)
> > (gdb) stepi
> > 0x000000000040113b	6	    for (; b<1; b++)
> > (gdb) stepi
> > 0x0000000000401141	6	    for (; b<1; b++)
> > (gdb) stepi
> > 0x0000000000401143	6	    for (; b<1; b++)
> > (gdb) stepi
> > 7	      c[b][d+1] = 0;
> > (gdb)
> > 
> > 
> > /*****************************************************
> > As showed, Line 6 is hit first and then hit Line 7 with stepi.
> > However, when using step, gdb is first hit Line 7 and then hit Line 6.
> > This is an inconsistent behaviors between stepi and step
> > *****************************************************/
> 
> Gdb is behaving consistently in the following sense:
> - when gdb is at a "recommended breakpoint location" it shows the source line
>   only with line number prefix.
> - otherwise, it shows the source line with both address and line number
> prefix.
> 
> So, what the stepi sequence shows it that the next "recommended breakpoint
> location" after line 5 is line 7, which is consistent with a step from line
> 5 to line 7.

I agree that at some time it will step to line 7 after executing line 6  and at
other times it will step to line 6 after executing line7  as they both at the
same iteration. 

However, my concern is that for the "first iteration or first time" line 6
should be hit ahead of line 7 no matter on whether we using step or using
stepi. That's to say, the first hit of Line 6 or Line 7 should be consistent
between step and stepi.