re PR tree-optimization/78899 (Vestorized loop with optmized mask stores motion is completely deleted after r242520.)

	PR tree-optimization/78899
	* tree-if-conv.c (version_loop_for_if_conversion): Instead of
	returning bool return struct loop *, NULL for failure and the new
	loop on success.
	(versionable_outer_loop_p): Don't version outer loop if it has
	dont_vectorized bit set.
	(tree_if_conversion): When versioning outer loop, ensure
	tree_if_conversion is performed also on the inner loop of the
	non-vectorizable outer loop copy.
	* tree-vectorizer.c (set_uid_loop_bbs): Formatting fix.  Fold
	LOOP_VECTORIZED in inner loop of the scalar outer loop and
	prevent vectorization of it.
	(vectorize_loops): For outer + inner LOOP_VECTORIZED, ensure
	the outer loop vectorization of the non-scalar version is attempted
	before vectorization of the inner loop in scalar version.  If
	outer LOOP_VECTORIZED guarded loop is not vectorized, prevent
	vectorization of its inner loop.
	* tree-vect-loop-manip.c (rename_variables_in_bb): If outer_loop
	has 2 inner loops, rename also on edges from bb whose single pred
	is outer_loop->header.  Fix typo in function comment.

	* gcc.target/i386/pr78899.c: New test.
	* gcc.dg/pr71077.c: New test.

From-SVN: r244238

1 files changed, 37 insertions, 5 deletions

diff --git a/gcc/tree-if-conv.c b/gcc/tree-if-conv.c
index 032182c..c12987e 100644
--- a/gcc/tree-if-conv.c
+++ b/gcc/tree-if-conv.c
@@ -2535,7 +2535,7 @@ combine_blocks (struct loop *loop)
    loop to execute.  The vectorizer pass will fold this
    internal call into either true or false.  */
 
-static bool
+static struct loop *
 version_loop_for_if_conversion (struct loop *loop)
 {
   basic_block cond_bb;
@@ -2566,7 +2566,7 @@ version_loop_for_if_conversion (struct loop *loop)
     ifc_bbs[i]->aux = saved_preds[i];
 
   if (new_loop == NULL)
-    return false;
+    return NULL;
 
   new_loop->dont_vectorize = true;
   new_loop->force_vectorize = false;
@@ -2574,7 +2574,7 @@ version_loop_for_if_conversion (struct loop *loop)
   gimple_call_set_arg (g, 1, build_int_cst (integer_type_node, new_loop->num));
   gsi_insert_before (&gsi, g, GSI_SAME_STMT);
   update_ssa (TODO_update_ssa);
-  return true;
+  return new_loop;
 }
 
 /* Return true when LOOP satisfies the follow conditions that will
@@ -2594,6 +2594,7 @@ static bool
 versionable_outer_loop_p (struct loop *loop)
 {
   if (!loop_outer (loop)
+      || loop->dont_vectorize
       || !loop->inner
       || loop->inner->next
       || !single_exit (loop)
@@ -2602,7 +2603,7 @@ versionable_outer_loop_p (struct loop *loop)
       || !single_pred_p (loop->latch)
       || !single_pred_p (loop->inner->latch))
     return false;
-  
+
   basic_block outer_exit = single_pred (loop->latch);
   basic_block inner_exit = single_pred (loop->inner->latch);
 
@@ -2789,7 +2790,10 @@ tree_if_conversion (struct loop *loop)
 {
   unsigned int todo = 0;
   bool aggressive_if_conv;
+  struct loop *rloop;
 
+ again:
+  rloop = NULL;
   ifc_bbs = NULL;
   any_pred_load_store = false;
   any_complicated_phi = false;
@@ -2829,8 +2833,31 @@ tree_if_conversion (struct loop *loop)
       struct loop *vloop
 	= (versionable_outer_loop_p (loop_outer (loop))
 	   ? loop_outer (loop) : loop);
-      if (!version_loop_for_if_conversion (vloop))
+      struct loop *nloop = version_loop_for_if_conversion (vloop);
+      if (nloop == NULL)
 	goto cleanup;
+      if (vloop != loop)
+	{
+	  /* If versionable_outer_loop_p decided to version the
+	     outer loop, version also the inner loop of the non-vectorized
+	     loop copy.  So we transform:
+	      loop1
+		loop2
+	     into:
+	      if (LOOP_VECTORIZED (1, 3))
+		{
+		  loop1
+		    loop2
+		}
+	      else
+		loop3 (copy of loop1)
+		  if (LOOP_VECTORIZED (4, 5))
+		    loop4 (copy of loop2)
+		  else
+		    loop5 (copy of loop4)  */
+	  gcc_assert (nloop->inner && nloop->inner->next == NULL);
+	  rloop = nloop->inner;
+	}
     }
 
   /* Now all statements are if-convertible.  Combine all the basic
@@ -2854,6 +2881,11 @@ tree_if_conversion (struct loop *loop)
       free (ifc_bbs);
       ifc_bbs = NULL;
     }
+  if (rloop != NULL)
+    {
+      loop = rloop;
+      goto again;
+    }
 
   return todo;
 }