--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/init/string2.C	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,104 @@
+// PR tree-optimization/71625 - missing strlen optimization on different
+// array initialization style
+//
+// Verify that strlen() calls with constant character array arguments
+// initialized with string constants are folded.  (This is a small
+// subset of pr71625).
+// { dg-do compile }
+// { dg-options "-O0 -Wno-error=narrowing -fdump-tree-gimple" }
+
+#define A(expr) do { typedef char A[-1 + 2 * !!(expr)]; } while (0)
+
+/* This is undefined but accepted without -Wpedantic.  Verify that
+   the size is zero.  */
+const char ax[] = { };
+
+void size0 ()
+{
+  A (sizeof ax == 0);
+}
+
+const char a0[] = { 'a', 'b', 'c', '\0' };
+
+int len0 ()
+{
+  return __builtin_strlen (a0);
+}
+
+// Verify that narrowing warnings are preserved.
+const signed char
+sa0[] = { 'a', 'b', 255, '\0' };    // { dg-warning "\\\[\(-Wnarrowing|-Woverflow\)" "" { target { ! c++98_only } } }
+
+int lens0 ()
+{
+  return __builtin_strlen ((const char*)sa0);
+}
+
+const unsigned char
+ua0[] = { 'a', 'b', -1, '\0' };     // { dg-warning "\\\[\(-Wnarrowing|-Woverflow\)" "" { target { ! c++98_only } } }
+
+int lenu0 ()
+{
+  return __builtin_strlen ((const char*)ua0);
+}
+
+const char c = 0;
+const char a1[] = { 'a', 'b', 'c', c };
+
+int len1 ()
+{
+  return __builtin_strlen (a1);
+}
+
+template <class T>
+int tmplen ()
+{
+  static const T
+    a[] = { 1, 2, 333, 0 };         // { dg-warning "\\\[\(-Wnarrowing|-Woverflow\)" }
+  return __builtin_strlen (a);
+}
+
+template int tmplen<char>();
+
+const wchar_t ws4[] = { 1, 2, 3, 4 };
+const wchar_t ws7[] = { 1, 2, 3, 4, 0, 0, 0 };
+const wchar_t ws9[9] = { 1, 2, 3, 4, 0 };
+
+void wsize ()
+{
+  A (sizeof ws4 == 4 * sizeof *ws4);
+  A (ws4[0] == 1 && ws4[1] == 2 && ws4[2] == 3 && ws4[3] == 4);
+
+  A (sizeof ws7 == 7 * sizeof *ws7);
+  A (ws7[0] == 1 && ws7[1] == 2 && ws7[2] == 3 && ws7[4] == 4
+     && !ws7[5] && !ws7[6]);
+
+  A (sizeof ws9 == 9 * sizeof *ws9);
+  A (ws9[0] == 1 && ws9[1] == 2 && ws9[2] == 3 && ws9[4] == 4
+     && !ws9[5] && !ws9[6] && !ws9[7] && !ws9[8]);
+}
+
+#if 0
+
+// The following aren't handled.
+
+const char &cref = c;
+const char a2[] = { 'a', 'b', 'c', cref };
+
+int len2 ()
+{
+  return __builtin_strlen (a2);
+}
+
+
+const char* const cptr = &cref;
+const char a3[] = { 'a', 'b', 'c', *cptr };
+
+int len3 ()
+{
+  return __builtin_strlen (a3);
+}
+
+#endif
+
+// { dg-final { scan-tree-dump-times "strlen" 0 "gimple" } }