[PATCH] tree-optimization/116796 - virtual LC SSA broken after unrolling

[Richard Biener]

When the unroller unloops loops it tracks whether it changes any
nesting relationship of remaining loops but when scanning a loops
preheader it fails to pass down the LC-SSA-invalidated bitmap, losing
the fact that an unrolled formerly inner loop can now be placed on
an exit of its outer loop.  The following fixes that.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

        PR tree-optimization/116796
        * cfgloopmanip.cc (fix_loop_placements): Get LC-SSA-invalidated
        bitmap and pass it on.
        (remove_path): Pass LC-SSA-invalidated to fix_loop_placements.
---
 gcc/cfgloopmanip.cc | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/gcc/cfgloopmanip.cc b/gcc/cfgloopmanip.cc
index 3707db2fdb3..d37d351fdf3 100644
--- a/gcc/cfgloopmanip.cc
+++ b/gcc/cfgloopmanip.cc
@@ -39,7 +39,7 @@ static void loop_redirect_edge (edge, basic_block);
 static void remove_bbs (basic_block *, int);
 static bool rpe_enum_p (const_basic_block, const void *);
 static int find_path (edge, basic_block **);
-static void fix_loop_placements (class loop *, bool *);
+static void fix_loop_placements (class loop *, bool *, bitmap);
 static bool fix_bb_placement (basic_block);
 static void fix_bb_placements (basic_block, bool *, bitmap);
 
@@ -415,7 +415,8 @@ remove_path (edge e, bool *irred_invalidated,
   /* Fix placements of basic blocks inside loops and the placement of
      loops in the loop tree.  */
   fix_bb_placements (from, irred_invalidated, loop_closed_ssa_invalidated);
-  fix_loop_placements (from->loop_father, irred_invalidated);
+  fix_loop_placements (from->loop_father, irred_invalidated,
+                      loop_closed_ssa_invalidated);
 
   if (local_irred_invalidated
       && loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS))
@@ -1048,7 +1049,8 @@ unloop (class loop *loop, bool *irred_invalidated,
    invalidate the information about irreducible regions.  */
 
 static void
-fix_loop_placements (class loop *loop, bool *irred_invalidated)
+fix_loop_placements (class loop *loop, bool *irred_invalidated,
+                    bitmap loop_closed_ssa_invalidated)
 {
   class loop *outer;
 
@@ -1064,7 +1066,7 @@ fix_loop_placements (class loop *loop, bool 
*irred_invalidated)
         to the loop.  So call fix_bb_placements to fix up the placement
         of the preheader and (possibly) of its predecessors.  */
       fix_bb_placements (loop_preheader_edge (loop)->src,
-                        irred_invalidated, NULL);
+                        irred_invalidated, loop_closed_ssa_invalidated);
       loop = outer;
     }
 }
-- 
2.43.0