Revert "Improve verification of loop->latch in verify_loop_structure"

2015-11-26  Tom de Vries  <tom@codesourcery.com>

	revert:
	2015-11-25  Tom de Vries  <tom@codesourcery.com>

	* cfgloop.c (find_single_latch): New function, factored out of ...
	(flow_loops_find): ... here.
	(verify_loop_structure): Improve verification of loop->latch.
	* cfgloop.h (find_single_latch): Declare.
	* omp-low.c (expand_omp_for_generic): Initialize latch of orig_loop.

From-SVN: r230967

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8609f0dcdaf3ab6eae504531df244c23cfcf3a6b..da80e714099d848f29642cb1d9d16480328110b6 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2015-11-26  Tom de Vries  <tom@codesourcery.com>
+
+       revert:
+       2015-11-25  Tom de Vries  <tom@codesourcery.com>
+
+       * cfgloop.c (find_single_latch): New function, factored out of ...
+       (flow_loops_find): ... here.
+       (verify_loop_structure): Improve verification of loop->latch.
+       * cfgloop.h (find_single_latch): Declare.
+       * omp-low.c (expand_omp_for_generic): Initialize latch of orig_loop.
+
 2015-11-26  Matthew Wahab  <matthew.wahab@arm.com>
 
        * config/aarch64/aarch64-simd-builtins.def:

diff --git a/gcc/cfgloop.c b/gcc/cfgloop.c
index e7cb78a5351246dd3534cd5d47f34ff25f761677..83a526276dbef8554b75709847645d844fbab4dd 100644 (file)
--- a/gcc/cfgloop.c
+++ b/gcc/cfgloop.c
@@ -388,33 +388,6 @@ bb_loop_header_p (basic_block header)
   return false;
 }
 
-/* Return the latch block for this header block, if it has just a single one.
-   Otherwise, return NULL.  */
-
-basic_block
-find_single_latch (struct loop* loop)
-{
-  basic_block header = loop->header;
-  edge_iterator ei;
-  edge e;
-  basic_block latch = NULL;
-
-  FOR_EACH_EDGE (e, ei, header->preds)
-    {
-      basic_block cand = e->src;
-      if (!flow_bb_inside_loop_p (loop, cand))
-       continue;
-
-      if (latch != NULL)
-       /* More than one latch edge.  */
-       return NULL;
-
-      latch = cand;
-    }
-
-  return latch;
-}
-
 /* Find all the natural loops in the function and save in LOOPS structure and
    recalculate loop_father information in basic block structures.
    If LOOPS is non-NULL then the loop structures for already recorded loops
@@ -509,10 +482,29 @@ flow_loops_find (struct loops *loops)
     {
       struct loop *loop = larray[i];
       basic_block header = loop->header;
+      edge_iterator ei;
+      edge e;
 
       flow_loop_tree_node_add (header->loop_father, loop);
       loop->num_nodes = flow_loop_nodes_find (loop->header, loop);
-      loop->latch = find_single_latch (loop);
+
+      /* Look for the latch for this header block, if it has just a
+        single one.  */
+      FOR_EACH_EDGE (e, ei, header->preds)
+       {
+         basic_block latch = e->src;
+
+         if (flow_bb_inside_loop_p (loop, latch))
+           {
+             if (loop->latch != NULL)
+               {
+                 /* More than one latch edge.  */
+                 loop->latch = NULL;
+                 break;
+               }
+             loop->latch = latch;
+           }
+       }
     }
 
   return loops;
@@ -1442,28 +1434,6 @@ verify_loop_structure (void)
              error ("loop %d%'s latch is not dominated by its header", i);
              err = 1;
            }
-         if (find_single_latch (loop) == NULL)
-           {
-             error ("loop %d%'s latch is is not the only latch", i);
-             err = 1;
-           }
-       }
-      else
-       {
-         if (loops_state_satisfies_p (LOOPS_MAY_HAVE_MULTIPLE_LATCHES))
-           {
-             if (find_single_latch (loop) != NULL)
-               {
-                 error ("loop %d%'s latch is missing", i);
-                 err = 1;
-               }
-           }
-         else
-           {
-             error ("loop %d%'s latch is missing, and loops may not have"
-                    " multiple latches", i);
-             err = 1;
-           }
        }
       if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES))
        {

diff --git a/gcc/cfgloop.h b/gcc/cfgloop.h
index 7faf591796ff6ccf22446f02c2e5ab988ee3905d..ee73bf994c18fc037e0de94b7b5c879182109893 100644 (file)
--- a/gcc/cfgloop.h
+++ b/gcc/cfgloop.h
@@ -270,7 +270,6 @@ bool mark_irreducible_loops (void);
 void release_recorded_exits (function *);
 void record_loop_exits (void);
 void rescan_loop_exit (edge, bool, bool);
-basic_block find_single_latch (struct loop*);
 
 /* Loop data structure manipulation/querying.  */
 extern void flow_loop_tree_node_add (struct loop *, struct loop *);

diff --git a/gcc/omp-low.c b/gcc/omp-low.c
index 0b44588b5a175ab0059a14f0e7c80e2d1d86ede3..f17a828330a8bcc63ecfda069b317daa0fc7f80a 100644 (file)
--- a/gcc/omp-low.c
+++ b/gcc/omp-low.c
@@ -8907,7 +8907,6 @@ expand_omp_for_generic (struct omp_region *region,
          orig_loop->header = l1_bb;
          /* The loop may have multiple latches.  */
          add_loop (orig_loop, new_loop);
-         orig_loop->latch = find_single_latch (orig_loop);
        }
     }
 }