[Bug tree-optimization/69468] New: tail merge should ignore private edge flags

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69468

            Bug ID: 69468
           Summary: tail merge should ignore private edge flags
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vries at gcc dot gnu.org
  Target Milestone: ---

https://gcc.gnu.org/ml/gcc-patches/2016-01/msg01880.html
...
> One reason is that an edge_flag EDGE_EXECUTABLE happens to be set, which
> prevents tail-merge from doing a merge.
<SNIP>
> Using first attached patch, which:
> - clears EDGE_EXECUTABLE in tail-merge, and

this shows a latent issue in tail-merging that it doesn't ignore
edge flags that are "private" (that is, they have random state upon
pass entry).
...