re PR tree-optimization/46886 (wrong code with -ftree-parallelize-loops -fno-tree-ch)

2012-03-08  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/46886
	* tree-flow.h (do_while_loop_p): Declare.
	* tree-ssa-loop-ch.c (do_while_loop_p): Export.
	* tree-parloops.c (parallelize_loops): Only parallelize do-while
	loops.

	* testsuite/libgomp.c/pr46886.c: New testcase.

From-SVN: r184010

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1c56ebe..7982452 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2012-02-08  Richard Guenther  <rguenther@suse.de>
+
+       PR tree-optimization/46886
+       * tree-flow.h (do_while_loop_p): Declare.
+       * tree-ssa-loop-ch.c (do_while_loop_p): Export.
+       * tree-parloops.c (parallelize_loops): Only parallelize do-while
+       loops.
+
 2012-02-08  Andrew MacLeod  <amacleod@redhat.com>
 
        * optabs.c (expand_atomic_load): Do not assume compare_and_swap will

diff --git a/gcc/tree-flow.h b/gcc/tree-flow.h
index ded7a3f..f4c4d5c 100644 (file)
--- a/gcc/tree-flow.h
+++ b/gcc/tree-flow.h
@@ -619,6 +619,9 @@ extern bool may_propagate_copy (tree, tree);
 extern bool may_propagate_copy_into_stmt (gimple, tree);
 extern bool may_propagate_copy_into_asm (tree);
 
+/* In tree-ssa-loop-ch.c  */
+bool do_while_loop_p (struct loop *);
+
 /* Affine iv.  */
 
 typedef struct

diff --git a/gcc/tree-parloops.c b/gcc/tree-parloops.c
index 28c450d..221f257 100644 (file)
--- a/gcc/tree-parloops.c
+++ b/gcc/tree-parloops.c
@@ -2183,7 +2183,10 @@ parallelize_loops (void)
          || loop_has_blocks_with_irreducible_flag (loop)
          || (loop_preheader_edge (loop)->src->flags & BB_IRREDUCIBLE_LOOP)
          /* FIXME: the check for vector phi nodes could be removed.  */
-         || loop_has_vector_phi_nodes (loop))
+         || loop_has_vector_phi_nodes (loop)
+         /* FIXME: transform_to_exit_first_loop does not handle not
+            header-copied loops correctly - see PR46886.  */
+         || !do_while_loop_p (loop))
        continue;
       estimated = max_stmt_executions_int (loop, false);
       /* FIXME: Bypass this check as graphite doesn't update the

diff --git a/gcc/tree-ssa-loop-ch.c b/gcc/tree-ssa-loop-ch.c
index 57e71b4..84e5a7d 100644 (file)
--- a/gcc/tree-ssa-loop-ch.c
+++ b/gcc/tree-ssa-loop-ch.c
@@ -104,7 +104,7 @@ should_duplicate_loop_header_p (basic_block header, struct loop *loop,
 
 /* Checks whether LOOP is a do-while style loop.  */
 
-static bool
+bool
 do_while_loop_p (struct loop *loop)
 {
   gimple stmt = last_stmt (loop->latch);

diff --git a/libgomp/ChangeLog b/libgomp/ChangeLog
index 8d9015d..daebf23 100644 (file)
--- a/libgomp/ChangeLog
+++ b/libgomp/ChangeLog
@@ -1,3 +1,8 @@
+2012-02-08  Richard Guenther  <rguenther@suse.de>
+
+       PR tree-optimization/46886
+       * testsuite/libgomp.c/pr46886.c: New testcase.
+
 2012-01-25  Matthias Klose  <doko@ubuntu.com>
 
        * config/linux/arm: Remove empty directory.

diff --git a/libgomp/testsuite/libgomp.c/pr46886.c b/libgomp/testsuite/libgomp.c/pr46886.c
new file mode 100644 (file)
index 0000000..fbdc4e1
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/pr46886.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-options "-O -ftree-parallelize-loops=4 -fno-tree-ch -fno-tree-dominator-opts" } */
+
+void abort(void);
+
+int d[1024], e[1024];
+
+int foo (void)
+{
+  int s = 0;
+  int i;
+  for (i = 0; i < 1024; i++)
+    s += d[i] - e[i];
+  return s;
+}
+
+int main ()
+{
+  int i;
+  for (i = 0; i < 1024; i++)
+    {
+      d[i] = i * 2;
+      e[i] = i;
+    }
+  if (foo () != 1023 * 1024 / 2)
+    abort ();
+  return 0;
+}