[Bug middle-end/87276] Buggy tree-ssa optimization introduced in revision 263875

[vincent-gcc at vinc17 dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87276

--- Comment #3 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> ---
Note: This may yield security issues since basically, this makes integer
overflow detection fail. In the testcase, after

      unsigned long uc;
      uc = (unsigned long) sum + (unsigned long) ps->e;

uc > 9223372036854775807, i.e. uc > LONG_MAX, is regarded as false instead of
true.