[Bug middle-end/69845] Expression getting incorrectly optimized after being rewritten by compiler

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69845

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
          Component|tree-optimization           |middle-end

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The problem is in fold:

In .003t.original:
  int B = A + 27685516;
  int C = B * 1067204616(OVF) + -887971669(OVF);


The reason why it works with -fwrapv is because GCC does not transform:

C = B * 1067204616(OVF) + -887971669(OVF)
C != 1676211843

Into
false
because first it does it into:
B*0x3f9c4008 != 0x6729aa28
And then notices 0x3f9c4008 is not a factor of 0x6729aa28.