tree-optimization/105226 - avoid splitting abnormal edges

Vectorizer loop versioning tries to version outer loops if possible
but fails to check whether it can actually split the single exit
edge as it will do.

2022-04-12  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/105226
	* tree-vect-loop-manip.c (vect_loop_versioning): Verify
	we can split the exit of an outer loop we choose to version.

	* gcc.dg/pr105226.c: New testcase.

(cherry picked from commit 62d5bb0f35fb6ec373eaac942755585a633528a0)

diff --git a/gcc/testsuite/gcc.dg/pr105226.c b/gcc/testsuite/gcc.dg/pr105226.c
new file mode 100644 (file)
index 0000000..9c4941d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr105226.c
@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+/* { dg-options "-Ofast" } */
+/* { dg-require-effective-target indirect_jumps } */
+
+#include <setjmp.h>
+struct longjmp_buf {
+  jmp_buf buf;
+};
+void g ();
+void f ()
+{
+  int i, n;
+  long *a;
+  long *args;
+  struct longjmp_buf b;
+  setjmp (b.buf);
+  for (;;)
+    {
+      for (i = 0; i < n; i++)
+        a[i] = args[i];
+      g ();
+    }
+}

diff --git a/gcc/tree-vect-loop-manip.c b/gcc/tree-vect-loop-manip.c
index d57108be5787f1685cb0131eef88397ea20d8031..99c546ef95231ae6840b7c83230196e5ba8e548f 100644 (file)
--- a/gcc/tree-vect-loop-manip.c
+++ b/gcc/tree-vect-loop-manip.c
@@ -3479,7 +3479,8 @@ vect_loop_versioning (loop_vec_info loop_vinfo,
        outermost = superloop_at_depth (loop, 1);
       /* And avoid applying versioning on non-perfect nests.  */
       while (loop_to_version != outermost
-            && single_exit (loop_outer (loop_to_version))
+            && (e = single_exit (loop_outer (loop_to_version)))
+            && !(e->flags & EDGE_COMPLEX)
             && (!loop_outer (loop_to_version)->inner->next
                 || vect_loop_vectorized_call (loop_to_version))
             && (!loop_outer (loop_to_version)->inner->next