--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/Wstringop-truncation-5.c	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,64 @@
+/* PR tree-optimization/87028 - false positive -Wstringop-truncation
+   strncpy with global variable source string
+   { dg-do compile }
+   { dg-options "-O2 -Wstringop-truncation" } */
+
+char *strncpy (char *, const char *, __SIZE_TYPE__);
+
+#define STR   "1234567890"
+
+struct S
+{
+  char a[5], b[5];
+};
+
+const char arr[] = STR;
+const char* const ptr = STR;
+
+const char arr2[][10] = { "123", STR };
+
+void test_literal (struct S *s)
+{
+  strncpy (s->a, STR, sizeof s->a - 1);     /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a[sizeof s->a - 1] = '\0';
+}
+
+void test_global_arr (struct S *s)
+{
+  strncpy (s->a, arr, sizeof s->a - 1);     /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a [sizeof s->a - 1] = '\0';
+}
+
+void test_global_arr2 (struct S *s)
+{
+  strncpy (s->a, arr2[1], sizeof s->a - 1); /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a [sizeof s->a - 1] = '\0';
+
+  strncpy (s->b, arr2[0], sizeof s->a - 1);
+}
+
+void test_global_ptr (struct S *s)
+{
+  strncpy (s->a, ptr, sizeof s->a - 1);     /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a [sizeof s->a - 1] = '\0';
+}
+
+void test_local_arr (struct S *s)
+{
+  const char arr[] = STR;
+  strncpy (s->a, arr, sizeof s->a - 1);
+  s->a [sizeof s->a - 1] = '\0';
+}
+
+void test_local_ptr (struct S *s)
+{
+  const char* const ptr = STR;
+  strncpy (s->a, ptr, sizeof s->a - 1);     /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a [sizeof s->a - 1] = '\0';
+}
+
+void test_compound_literal (struct S *s)
+{
+  strncpy (s->a, (char[]){ STR }, sizeof s->a - 1);
+  s->a [sizeof s->a - 1] = '\0';
+}