[Bug tree-optimization/68083] [6 Regression] wrong code at -O3 on x86_64-linux-gnu

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68083

Alexandre Oliva <aoliva at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |aoliva at gcc dot gnu.org

--- Comment #6 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Created attachment 36622
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36622&action=edit
Patch I'm testing to fix the problem

This patch stops ifcombine from introducing this kind of undefined behavior. 
I'm testing it now, and I'll post it to the list if that completes
successfully.