[Bug c/64249] New: Missing warning for if (A) else if (A)

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64249

            Bug ID: 64249
           Summary: Missing warning for if (A) else if (A)
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mpolacek at gcc dot gnu.org

E.g. here we should warn:
  if (conditionX)
    {
    }
  else if (conditionY)
    ...
when the two conditions don't have side-effects and are operand_equal_p.

Cf. https://gcc.gnu.org/ml/gcc-patches/2014-12/msg00875.html