[Bug tree-optimization/65440] New: pass_lim misses support for predicated code motion

["vries at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65440

            Bug ID: 65440
           Summary: pass_lim misses support for predicated code motion
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vries at gcc dot gnu.org

tree-ssa-loop-im.c (
https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/tree-ssa-loop-im.c;h=9aba79ba776944ec6fba8459354deabe8c126b75;hb=HEAD#l74
):
...
/* TODO:  Support for predicated code motion.  I.e.

   while (1)
     {
       if (cond)
     {
       a = inv;
       something;
     }
     }

   Where COND and INV are invariants, but evaluating INV may trap or be
   invalid from some other reason if !COND.  This may be transformed to

   if (cond)
     a = inv;
   while (1)
     {
       if (cond)
     something;
     }  */
...