re PR rtl-optimization/13985 (ICE in gcc.c-torture/compile/930621-1.c)

	PR optimization/13985
	* cfgloopmanip.c (fix_loop_placements): New prototype.
	Call fix_bb_placements on the preheader of loops that have
	been reparented.
	(remove_path): Adjust call to fix_loop_placements.

From-SVN: r81112

1 files changed, 10 insertions, 3 deletions

diff --git a/gcc/cfgloopmanip.c b/gcc/cfgloopmanip.c
index 59ae4a1ed7a..e3807801d23 100644
--- a/gcc/cfgloopmanip.c
+++ b/gcc/cfgloopmanip.c
@@ -41,7 +41,7 @@ static bool rpe_enum_p (basic_block, void *);
 static int find_path (edge, basic_block **);
 static bool alp_enum_p (basic_block, void *);
 static void add_loop (struct loops *, struct loop *);
-static void fix_loop_placements (struct loop *);
+static void fix_loop_placements (struct loops *, struct loop *);
 static bool fix_bb_placement (struct loops *, basic_block);
 static void fix_bb_placements (struct loops *, basic_block);
 static void place_new_loop (struct loops *, struct loop *);
@@ -413,7 +413,7 @@ remove_path (struct loops *loops, edge e)
   /* Fix placements of basic blocks inside loops and the placement of
      loops in the loop tree.  */
   fix_bb_placements (loops, from);
-  fix_loop_placements (from->loop_father);
+  fix_loop_placements (loops, from->loop_father);
 
   return true;
 }
@@ -668,7 +668,7 @@ fix_loop_placement (struct loop *loop)
    It is used in case when we removed some edges coming out of LOOP, which
    may cause the right placement of LOOP inside loop tree to change.  */
 static void
-fix_loop_placements (struct loop *loop)
+fix_loop_placements (struct loops *loops, struct loop *loop)
 {
   struct loop *outer;
 
@@ -677,6 +677,13 @@ fix_loop_placements (struct loop *loop)
       outer = loop->outer;
       if (!fix_loop_placement (loop))
         break;
+
+      /* Changing the placement of a loop in the loop tree may alter the
+	 validity of condition 2) of the description of fix_bb_placement
+	 for its preheader, because the successor is the header and belongs
+	 to the loop.  So call fix_bb_placements to fix up the placement
+	 of the preheader and (possibly) of its predecessors.  */
+      fix_bb_placements (loops, loop_preheader_edge (loop)->src);
       loop = outer;
     }
 }