diff --git a/gcc/testsuite/c-c++-common/pr118205.c b/gcc/testsuite/c-c++-common/pr118205.c
new file mode 100644
index 00000000000..c98f8d84a1b
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr118205.c
@@ -0,0 +1,25 @@
+/* PR tree-optimization/118205 */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target fgraphite } */
+/* { dg-require-effective-target pthread } */
+/* { dg-options "-O -floop-parallelize-all -ftree-parallelize-loops=2" } */
+
+int x;
+void g(int);
+int f() {
+  unsigned res = 0;
+  int arr[] = {};
+  int y = 0;
+  for (unsigned int i = 1; i; i++)
+    {
+      for (int n = 0; n < 2; n++)
+	{
+	  g(arr[i]);
+	  res = y > x ? y : x;
+	  y = res;
+        }
+      g(arr[i]);
+    }
+  return res;
+}
diff --git a/gcc/tree-parloops.cc b/gcc/tree-parloops.cc
index 8427c287a6a..42183297399 100644
--- a/gcc/tree-parloops.cc
+++ b/gcc/tree-parloops.cc
@@ -948,7 +948,7 @@ reduction_phi (reduction_info_table_type *reduction_list, gimple *phi)
 {
   struct reduction_info tmpred, *red;
 
-  if (reduction_list->is_empty () || phi == NULL)
+  if (reduction_list->is_empty () || phi == NULL || !is_a <gphi *> (phi))
     return NULL;
 
   if (gimple_uid (phi) == (unsigned int)-1