Fix boostrap failure in tree-ssa-loop-ch.cc

I managed to mix up patch and its WIP version in previous commit.
This patch adds the missing edge iterator and also fixes a side
case where new loop header would have multiple latches.

gcc/ChangeLog:

	* tree-ssa-loop-ch.cc (ch_base::copy_headers): Fix previous
	commit.

diff --git a/gcc/tree-ssa-loop-ch.cc b/gcc/tree-ssa-loop-ch.cc
index 560df39893ef3db48ac72f570773fe8cf0647575..0025bc16e432434c780e30c2385029d00cb11326 100644 (file)
--- a/gcc/tree-ssa-loop-ch.cc
+++ b/gcc/tree-ssa-loop-ch.cc
@@ -484,7 +484,10 @@ ch_base::copy_headers (function *fun)
       /* Ensure that the header will have just the latch as a predecessor
         inside the loop.  */
       if (!single_pred_p (exit->dest))
-       exit = single_pred_edge (split_edge (exit));
+       {
+         header = split_edge (exit);
+         exit = single_pred_edge (header);
+       }
 
       entry = loop_preheader_edge (loop);
 
@@ -547,16 +550,17 @@ ch_base::copy_headers (function *fun)
       /* Find correct latch.  We only duplicate chain of conditionals so
         there should be precisely two edges to the new header.  One entry
         edge and one to latch.  */
+      edge_iterator ei;
+      edge e;
       FOR_EACH_EDGE (e, ei, loop->header->preds)
        if (header != e->src)
          {
            loop->latch = e->src;
            break;
          }
-      /* Ensure that the latch and the preheader is simple (we know that they
-        are not now, since there was the loop exit condition.  */
-      split_edge (loop_preheader_edge (loop));
-      split_edge (loop_latch_edge (loop));
+      /* Ensure that the latch is simple.  */
+      if (!single_succ_p (loop_latch_edge (loop)->src))
+       split_edge (loop_latch_edge (loop));
 
       if (dump_file && (dump_flags & TDF_DETAILS))
        {
@@ -572,8 +576,6 @@ ch_base::copy_headers (function *fun)
 
   if (changed)
     {
-      if (flag_checking)
-       verify_loop_structure ();
       update_ssa (TODO_update_ssa);
       /* After updating SSA form perform CSE on the loop header
         copies.  This is esp. required for the pass before