[Bug middle-end/81320] -Wlogical-op diagnostic depends on comparison' order

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81320

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2017-07-11
     Ever confirmed|0                           |1

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
We fail to warn in f2 because we compare the expression in the conditional
sequentially, but that doesn't work due to left-to-right associativity: we
compare
i == 0 with i == 1
and then
i == 0 || i == 1 with i == 0.

The fix would probably be to keep [low, high] pairs for every comparison and
then compare the pairs.