[Bug c/79174] xorswap *x^=*y^(*y=*x) : sometime don't work with optimisation

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79174

Marc Glisse <glisse at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #1 from Marc Glisse <glisse at gcc dot gnu.org> ---
x.c:6:16: warning: operation on '*py' may be undefined [-Wsequence-point]
   *px^=*py^(*py=*px);
            ~~~~^~~~~

(please never post random lines, always a complete program that we can just
copy-paste)