1 files changed, 119 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-2.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-2.c
new file mode 100644
index 00000000000..6aaea8ecb38
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-2.c
@@ -0,0 +1,119 @@
+/* { dg-do compile } */ 
+/* { dg-options "-O2 -fdump-tree-vrp1-stats -fdump-tree-dom1-stats" } */
+
+void foo();
+void bla();
+void bar();
+
+/* In the following two cases, we should be able to thread edge through
+   the loop header.  */
+
+void thread_entry_through_header (void)
+{
+  int i;
+
+  for (i = 0; i < 170; i++)
+    bla ();
+}
+
+void thread_latch_through_header (void)
+{
+  int i = 0;
+  int first = 1;
+
+  do
+    {
+      if (first)
+	foo ();
+
+      first = 0;
+      bla ();
+    } while (i++ < 100);
+}
+
+/* This is a TODO -- it is correct to thread both entry and latch edge through
+   the header, but we do not handle this case yet.  */
+
+void dont_thread_1 (void)
+{
+  int i = 0;
+  int first = 1;
+
+  do
+    {
+      if (first)
+	foo ();
+      else
+	bar ();
+
+      first = 0;
+      bla ();
+    } while (i++ < 100);
+}
+
+/* Avoid threading in the following two cases, to prevent creating subloops.  */
+
+void dont_thread_2 (int first)
+{
+  int i = 0;
+
+  do
+    {
+      if (first)
+	foo ();
+      else
+	bar ();
+
+      first = 0;
+      bla ();
+    } while (i++ < 100);
+}
+
+void dont_thread_3 (int nfirst)
+{
+  int i = 0;
+  int first = 0;
+
+  do
+    {
+      if (first)
+	foo ();
+      else
+	bar ();
+
+      first = nfirst;
+      bla ();
+    } while (i++ < 100);
+}
+
+/* Avoid threading in this case, in order to avoid creating loop with
+   multiple entries.  */
+
+void dont_thread_4 (int a, int nfirst)
+{
+  int i = 0;
+  int first;
+
+  if (a)
+    first = 0;
+  else
+    first = 1;
+
+  do
+    {
+      if (first)
+	foo ();
+      else
+	bar ();
+
+      first = nfirst;
+      bla ();
+    } while (i++ < 100);
+}
+
+/* { dg-final { scan-tree-dump-times "Jumps threaded: 1" 1 "vrp1"} } */
+/* { dg-final { scan-tree-dump-times "Jumps threaded: 2" 0 "vrp1"} } */
+/* { dg-final { scan-tree-dump-times "Jumps threaded: 1" 0 "dom1"} } */
+/* { dg-final { scan-tree-dump-times "Jumps threaded: 2" 1 "dom1"} } */
+/* { dg-final { cleanup-tree-dump "dom1" } } */
+/* { dg-final { cleanup-tree-dump "vrp1" } } */