[Bug tree-optimization/41488] IVOpts cannot coalesce multiple induction variables

[xinliangli at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41488

--- Comment #5 from davidxl <xinliangli at gmail dot com> ---
Alternative approach -- introduce a special forward propagation before or after
the ivopt to get rid of the redundant iv. This propagation needs to propagate
through header phi.