diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6fdb1b62d2d..63779d362c2 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2018-08-22  Richard Sandiford  <richard.sandiford@arm.com>
+
+	PR tree-optimization/86725
+	* tree-vect-loop.c (vect_is_simple_reduction): When treating
+	an outer loop phi as a double reduction, make sure that the
+	single user of the phi result is an inner loop phi.
+
 2018-08-22  Richard Sandiford  <richard.sandiford@arm.com>
 
 	* tree-vect-data-refs.c (vect_analyze_group_access_1): Convert
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 9c624ff0739..3117afaa82d 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-08-22  Richard Sandiford  <richard.sandiford@arm.com>
+
+	PR tree-optimization/86725
+	* gcc.dg/vect/no-scevccp-pr86725-1.c: New test.
+
 2018-08-22  Richard Sandiford  <richard.sandiford@arm.com>
 
 	* gcc.dg/vect/vect-avg-16.c: New test.
diff --git a/gcc/testsuite/gcc.dg/vect/no-scevccp-pr86725-1.c b/gcc/testsuite/gcc.dg/vect/no-scevccp-pr86725-1.c
new file mode 100644
index 00000000000..3bc63a6552b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/no-scevccp-pr86725-1.c
@@ -0,0 +1,26 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-O -w" } */
+
+int foo;
+int
+nr (int xe, int z)
+{
+  int oo, wo = 0;
+
+  for (oo = 0; oo < 4; ++oo)
+    {
+      int qq;
+
+      int old_wo = wo;
+      for (qq = 0; qq < 2; ++qq)
+        {
+          wo = z + qq + old_wo;
+          xe += wo;
+        }
+    }
+  foo = wo;
+  return xe;
+}
+
+/* { dg-final { scan-tree-dump-not "double reduction: wo" "vect" } } */
+/* { dg-final { scan-tree-dump-not "OUTER LOOP VECTORIZED" "vect" } } */
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index db92f76c74f..f21d995fdb9 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -2992,6 +2992,7 @@ vect_is_simple_reduction (loop_vec_info loop_info, stmt_vec_info phi_info,
           && loop->inner
           && flow_bb_inside_loop_p (loop->inner, gimple_bb (def1))
           && is_gimple_assign (def1)
+	  && is_a <gphi *> (phi_use_stmt)
 	  && flow_bb_inside_loop_p (loop->inner, gimple_bb (phi_use_stmt)))
         {
           if (dump_enabled_p ())