re PR tree-optimization/46177 (ICE: in prop_phis, at…

re PR tree-optimization/46177 (ICE: in prop_phis, at tree-loop-distribution.c:327 with -fno-tree-copy-prop -ftree-loop-distribution)

2010-11-09  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/46177
	* tree-loop-distribution.c (prop_phis): Remove.
	(generate_builtin): Re-use the old loop exit edge to avoid
	needing to update PHI nodes.

	* gcc.dg/pr46177-2.c: New testcase.

From-SVN: r166492

gcc/ChangeLog

+2010-11-09  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/46177
+	* tree-loop-distribution.c (prop_phis): Remove.
+	(generate_builtin): Re-use the old loop exit edge to avoid
+	needing to update PHI nodes.
+
 2010-11-09  Joern Rennecke  <amylaar@spamcop.net>
 
 	* ix86_expand_split_stack_prologue (args_size): Change type to

gcc/testsuite/ChangeLog

 2010-11-09  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/46177
+	* gcc.dg/pr46177-2.c: New testcase.
+
+2010-11-09  Richard Guenther  <rguenther@suse.de>
+
 	PR testsuite/46312
 	* gcc.dg/vec-scal-opt.c: Move ...
 	* gcc.dg/vect/vect-scal-opt.c: ... here.

gcc/testsuite/gcc.dg/pr46177-2.c

+/* { dg-do compile } */
+/* { dg-options "-O -fno-tree-copy-prop -ftree-loop-distribution" } */
+
+int A[30], B[30];
+
+void
+foo (int j)
+{
+  int i, k;
+  for (k = 0; k < 10; k++)
+    if (j)
+      {
+	for (; j < k; j++)
+	  ;
+	for (i = 0; i < k; i++)
+	  A[i] = B[i] = 0;
+      }
+}

gcc/tree-loop-distribution.c

@@ -311,31 +311,6 @@ generate_memset_zero (gimple stmt, tree op0, tree nb_iter,
   return res;
 }
 
-/* Propagate phis in BB b to their uses and remove them.  */
-
-static void
-prop_phis (basic_block b)
-{
-  gimple_stmt_iterator psi;
-
-  for (psi = gsi_start_phis (b); !gsi_end_p (psi); )
-    {
-      gimple phi = gsi_stmt (psi);
-      tree def = gimple_phi_result (phi);
-
-      if (!is_gimple_reg (def))
-	mark_virtual_phi_result_for_renaming (phi);
-      else
-	{
-	  tree use = gimple_phi_arg_def (phi, 0);
-	  gcc_assert (gimple_phi_num_args (phi) == 1);
-	  replace_uses_by (def, use);
-	}
-
-      remove_phi_node (&psi, true);
-    }
-}
-
 /* Tries to generate a builtin function for the instructions of LOOP
    pointed to by the bits set in PARTITION.  Returns true when the
    operation succeeded.  */
@@ -405,11 +380,13 @@ generate_builtin (struct loop *loop, bitmap partition, bool copy_p)
   if (res && !copy_p)
     {
       unsigned nbbs = loop->num_nodes;
-      basic_block src = loop_preheader_edge (loop)->src;
-      basic_block dest = single_exit (loop)->dest;
-      prop_phis (dest);
-      make_edge (src, dest, EDGE_FALLTHRU);
+      edge exit = single_exit (loop);
+      basic_block src = loop_preheader_edge (loop)->src, dest = exit->dest;
+      redirect_edge_pred (exit, src);
+      exit->flags &= ~(EDGE_TRUE_VALUE|EDGE_FALSE_VALUE);
+      exit->flags |= EDGE_FALLTHRU;
       cancel_loop_tree (loop);
+      rescan_loop_exit (exit, false, true);
 
       for (i = 0; i < nbbs; i++)
 	delete_basic_block (bbs[i]);