[gcc r12-8104] tree-optimization/105226 - avoid splitting abnormal edges

[gcc r12-8104] tree-optimization/105226 - avoid splitting abnormal edges

[Richard Biener]

https://gcc.gnu.org/g:62d5bb0f35fb6ec373eaac942755585a633528a0

commit r12-8104-g62d5bb0f35fb6ec373eaac942755585a633528a0
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Apr 12 09:40:15 2022 +0200

    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.cc (vect_loop_versioning): Verify
            we can split the exit of an outer loop we choose to version.
    
            * gcc.dg/pr105226.c: New testcase.

Diff:
---
 gcc/testsuite/gcc.dg/pr105226.c | 23 +++++++++++++++++++++++
 gcc/tree-vect-loop-manip.cc     |  3 ++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/gcc/testsuite/gcc.dg/pr105226.c b/gcc/testsuite/gcc.dg/pr105226.c
new file mode 100644
index 00000000000..9c4941dc6fc
--- /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.cc b/gcc/tree-vect-loop-manip.cc
index a7bbc916bbc..63fb6f669a0 100644
--- a/gcc/tree-vect-loop-manip.cc
+++ b/gcc/tree-vect-loop-manip.cc
@@ -3524,7 +3524,8 @@ 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