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From: "hubicka at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/54717] [4.8 Regression] Runtime regression: polyhedron test "rnflow" degraded
Date: Wed, 14 Nov 2012 20:11:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54717

Jan Hubicka <hubicka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hubicka at gcc dot gnu.org

--- Comment #14 from Jan Hubicka <hubicka at gcc dot gnu.org> 2012-11-14 20:11:17 UTC ---
Hmm, the optimize_edge_for_speed never returns false here. The problem is that
patch assumes that interesting successors of block with partial anticipance are
blocks with partial anticipance. The anticipance however could be full and it
seems that full anticipance do not imply partial one
Index: tree-ssa-pre.c
===================================================================
*** tree-ssa-pre.c      (revision 193503)
--- tree-ssa-pre.c      (working copy)
*************** do_partial_partial_insertion (basic_bloc
*** 3525,3531 ****
                 may cause regressions on the speed path.  */
              FOR_EACH_EDGE (succ, ei, block->succs)
                {
!                 if (bitmap_set_contains_value (PA_IN (succ->dest), val))
                    {
                      if (optimize_edge_for_speed_p (succ))
                        do_insertion = true;
--- 3525,3532 ----
                 may cause regressions on the speed path.  */
              FOR_EACH_EDGE (succ, ei, block->succs)
                {
!                 if (bitmap_set_contains_value (PA_IN (succ->dest), val)
!                     || bitmap_set_contains_value (ANTIC_IN (succ->dest),
val))
                    {
                      if (optimize_edge_for_speed_p (succ))
                        do_insertion = true;