--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/Wstringop-overflow-21.c	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,59 @@
+/* PR middle-end/92312 - bogus -Wstringop-overflow storing into a trailing
+   array backed by larger buffer
+   { dg-do compile }
+   { dg-options "-O2 -Wall -Wno-array-bounds" } */
+
+struct S0 { char a, b[0]; };
+
+void sink (void*);
+
+void test_memset_zero_length (void)
+{
+  char a[3];
+  struct S0 *p = (struct S0*)a;
+  p->a = 0;
+  __builtin_memset (p->b, 0, 2);
+  sink (p);
+
+  __builtin_memset (p->b, 0, 3);    // { dg-warning "\\\[-Wstringop-overflow" }
+  sink (p);
+}
+
+void test_store_zero_length (int i)
+{
+  char a[3];
+  struct S0 *p = (struct S0*)a;
+  p->a = 0;
+  p->b[0] = 0;
+  p->b[1] = 1;                      // { dg-bogus "\\\[-Wstringop-overflow" }
+  p->b[2] = 2;                      // { dg-warning "\\\[-Wstringop-overflow" }
+  p->b[i] = 2;
+  sink (p);
+}
+
+
+struct Sx { char a, b[]; };
+
+void test_memset_flexarray (int i)
+{
+  char a[3];
+  struct Sx *p = (struct Sx*)a;
+  p->a = 0;
+  __builtin_memset (p->b, 0, 2);
+  sink (p);
+
+  __builtin_memset (p->b, 0, 3);    // { dg-warning "\\\[-Wstringop-overflow" }
+  sink (p);
+}
+
+void test_store_flexarray (int i)
+{
+  char a[3];
+  struct Sx *p = (struct Sx*)a;
+  p->a = 0;
+  p->b[0] = 0;
+  p->b[1] = 1;                      // { dg-bogus "\\\[-Wstringop-overflow" }
+  p->b[2] = 1;                      // { dg-warning "\\\[-Wstringop-overflow" }
+  p->b[i] = 2;
+  sink (p);
+}