[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 #5 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
(In reply to Marek Polacek from comment #4)
> Why does it think that a.1_5 must be 0?

That's because VRP is innocent here after all, it's the forwprop1 what does

-  _6 = a.1_5 & 1;
-  _7 = (_Bool) _6;
+  _7 = (_Bool) a.1_5;

More (hopefully) tomorrow...