diff --git a/gcc/testsuite/gcc.dg/torture/pr117333.c b/gcc/testsuite/gcc.dg/torture/pr117333.c
new file mode 100644
index 00000000000..38c1b5493a5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr117333.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+
+struct s
+{
+  unsigned long ul;
+  int i;
+  char ac[];
+};
+
+const struct s gs = { 3, -4, "abcdef" };
+
+void copy_s(struct s*d, const struct s*s)
+{
+  *d = *s;
+}
+
+unsigned test(struct s*ps, _Bool direct)
+{
+  if(direct)
+    *ps = gs;
+  else
+    copy_s(ps, &gs);
+  return sizeof(*ps);
+}
+
+unsigned size(void)
+{
+  return sizeof(gs);
+}
diff --git a/gcc/tree-data-ref.cc b/gcc/tree-data-ref.cc
index de234c65e94..1fdfef282c7 100644
--- a/gcc/tree-data-ref.cc
+++ b/gcc/tree-data-ref.cc
@@ -3004,6 +3004,8 @@ dr_may_alias_p (const struct data_reference *a, const struct data_reference *b,
 	  && DR_BASE_ADDRESS (b)
 	  && operand_equal_p (DR_BASE_ADDRESS (a), DR_BASE_ADDRESS (b))
 	  && operand_equal_p (DR_OFFSET (a), DR_OFFSET (b))
+	  && tree_size_a
+	  && tree_size_b
 	  && poly_int_tree_p (tree_size_a)
 	  && poly_int_tree_p (tree_size_b)
 	  && !ranges_maybe_overlap_p (wi::to_poly_widest (DR_INIT (a)),