Handle double reduction in parloops

2015-07-28  Tom de Vries  <tom@codesourcery.com>

	* tree-parloops.c (reduc_stmt_res): New function.
	(initialize_reductions, add_field_for_reduction)
	(create_phi_for_local_result, create_loads_for_reductions)
	(create_stores_for_reduction, build_new_reduction): Handle case that
	reduc_stmt is a phi.
	(gather_scalar_reductions): Allow double_reduc reductions.

	* gcc.dg/autopar/uns-outer-4.c: Remove xfail on scan for parallelizing
	outer loop.

	* testsuite/libgomp.c/uns-outer-4.c: New test.

git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@226300 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 36 insertions, 0 deletions

diff --git a/libgomp/testsuite/libgomp.c/uns-outer-4.c b/libgomp/testsuite/libgomp.c/uns-outer-4.c
new file mode 100644
index 00000000000..cd646a54133
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/uns-outer-4.c
@@ -0,0 +1,36 @@
+/* { dg-do run } */
+/* { dg-additional-options "-ftree-parallelize-loops=2" } */
+
+void abort (void);
+
+unsigned int g_sum = 1;
+
+unsigned int x[500][500];
+
+void __attribute__((noinline,noclone))
+parloop (int N)
+{
+  int i, j;
+  unsigned int sum;
+
+  /* Double reduction is detected, outer loop is parallelized.  */
+  sum = 0;
+  for (i = 0; i < N; i++)
+    for (j = 0; j < N; j++)
+      sum += x[i][j];
+
+  g_sum = sum;
+}
+
+int
+main (void)
+{
+  x[234][432] = 2;
+
+  parloop (500);
+
+  if (g_sum != 2)
+    abort ();
+
+  return 0;
+}