[Bug c/95057] New: missing -Wunused-but-set-variable warning on multiple assignments, not all of them used

[vincent-gcc at vinc17 dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95057

            Bug ID: 95057
           Summary: missing -Wunused-but-set-variable warning on multiple
                    assignments, not all of them used
           Product: gcc
           Version: 10.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vincent-gcc at vinc17 dot net
  Target Milestone: ---

With -Wunused-but-set-variable, GCC does not warn in the following cases:

int f (int i)
{
  int j;
  j = i + 1;  /* unused */
  j = i + 2;
  return j;
}

int g (int i)
{
  int j, k;
  j = i + 1;
  k = j + 1;
  j = i + 2;  /* unused */
  return k;
}

Note: it is possible that PR44677 may be regarded as a particular case of this
bug.