[Bug tree-optimization/59014] [4.9 Regression] wrong code at -Os and above on x86_64-linux-gnu

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59014

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
It seems we create wrong ASSERT_EXPR:

  a.1_5 = a;
  _7 = (_Bool) a.1_5;
  _8 = _4 | _7; 
  if (_8 != 0)
    goto <bb 5>; 
  else
    goto <bb 6>; 

  <bb 6>: 
  a.1_15 = ASSERT_EXPR <a.1_5, a.1_5 == 0>;

Why does it think that a.1_5 must be 0?