[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 #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
I'd say this is .vrp1.  In .mergephi2, we have

  <bb 4>: 
  a.1_11 = a.1_5;
  d = a.1_11;
  return 0;

but in .vrp1:

  <bb 4>: 
  a.1_13 = 0;
  a.1_11 = 0;
  d = 0;
  return 0;

And yeah, the bug goes away with -fno-tree-vrp.