Don't parallelize loops containing phis with addr_exprs

2016-01-10  Tom de Vries  <tom@codesourcery.com>

	PR tree-optimization/69062
	* tree-parloops.c (loop_has_phi_with_address_arg): New function.
	(parallelize_loops): Don't paralelize loop that has phi with address
	arg.

	* gcc.dg/autopar/pr69062.c: New test.

From-SVN: r232199

1 files changed, 34 insertions, 0 deletions

diff --git a/gcc/tree-parloops.c b/gcc/tree-parloops.c
index 394aba8..5bd9c06 100644
--- a/gcc/tree-parloops.c
+++ b/gcc/tree-parloops.c
@@ -2640,6 +2640,37 @@ try_create_reduction_list (loop_p loop,
   return true;
 }
 
+/* Return true if LOOP contains phis with ADDR_EXPR in args.  */
+
+static bool
+loop_has_phi_with_address_arg (struct loop *loop)
+{
+  basic_block *bbs = get_loop_body (loop);
+  bool res = false;
+
+  unsigned i, j;
+  gphi_iterator gsi;
+  for (i = 0; i < loop->num_nodes; i++)
+    for (gsi = gsi_start_phis (bbs[i]); !gsi_end_p (gsi); gsi_next (&gsi))
+      {
+	gphi *phi = gsi.phi ();
+	for (j = 0; j < gimple_phi_num_args (phi); j++)
+	  {
+	    tree arg = gimple_phi_arg_def (phi, j);
+	    if (TREE_CODE (arg) == ADDR_EXPR)
+	      {
+		/* This should be handled by eliminate_local_variables, but that
+		   function currently ignores phis.  */
+		res = true;
+		goto end;
+	      }
+	  }
+      }
+ end:
+  free (bbs);
+  return res;
+}
+
 /* Detect parallel loops and generate parallel code using libgomp
    primitives.  Returns true if some loop was parallelized, false
    otherwise.  */
@@ -2734,6 +2765,9 @@ parallelize_loops (void)
       if (!try_create_reduction_list (loop, &reduction_list))
 	continue;
 
+      if (loop_has_phi_with_address_arg (loop))
+	continue;
+
       if (!flag_loop_parallelize_all
 	  && !loop_parallel_p (loop, &parloop_obstack))
 	continue;