diff --git a/gcc/testsuite/gcc.dg/vect/vect-outer-pr117510.c b/gcc/testsuite/gcc.dg/vect/vect-outer-pr117510.c
new file mode 100644
index 00000000000..e50b67ce040
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-outer-pr117510.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target vect_double } */
+/* { dg-additional-options "-O3" } */
+
+void f(int n, int m, double *a)
+{
+  a = __builtin_assume_aligned (a, __BIGGEST_ALIGNMENT__);
+  for (int i = 0; i < n; i++)
+    for (int j = 0; j < m; j++)
+      a[i] += 2*a[i] + j;
+}
+
+/* { dg-final { scan-tree-dump "OUTER LOOP VECTORIZED" "vect" } } */
diff --git a/gcc/tree-ssa-loop-unswitch.cc b/gcc/tree-ssa-loop-unswitch.cc
index 847f7ac739f..88516fdb0a1 100644
--- a/gcc/tree-ssa-loop-unswitch.cc
+++ b/gcc/tree-ssa-loop-unswitch.cc
@@ -1256,7 +1256,11 @@ find_loop_guard (class loop *loop, vec<gimple *> &dbg_to_reset)
 	  guard_edge = NULL;
 	  goto end;
 	}
-      if (!empty_bb_without_guard_p (loop, bb, dbg_to_reset))
+      /* If any of the not skipped blocks has side-effects or defs with
+	 uses outside of the loop we cannot hoist the guard.  */
+      if (!dominated_by_p (CDI_DOMINATORS,
+			   bb, guard_edge == te ? fe->dest : te->dest)
+	  && !empty_bb_without_guard_p (loop, bb, dbg_to_reset))
 	{
 	  if (dump_enabled_p ())
 	    dump_printf_loc (MSG_MISSED_OPTIMIZATION, loc,