--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/strlenopt-49.c	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,53 @@
+/* PR tree-optimization/86428 - strlen of const array initialized with
+   a string of the same length not folded
+   { dg-do compile }
+   { dg-options "-O0 -Wall -fdump-tree-gimple" } */
+
+#include "strlenopt.h"
+
+const char a1[1] = "\0";
+const char a2[2] = "1\0";
+const char a3[3] = "12\0";
+const char a8[8] = "1234567\0";
+const char a9[9] = "12345678\0";
+
+const char ax[9] = "12345678\0\0\0\0";   /* { dg-warning "initializer-string for array of chars is too long" } */
+const char ay[9] = "\00012345678\0\0\0\0";   /* { dg-warning "initializer-string for array of chars is too long" } */
+
+
+int len1 (void)
+{
+  size_t len0 = strlen (a1);
+  return len0;
+}
+
+int len (void)
+{
+  size_t len = strlen (a2) + strlen (a3) + strlen (a8) + strlen (a9);
+  return len;
+}
+
+int lenx (void)
+{
+  size_t lenx = strlen (ax);
+  return lenx;
+}
+
+int leny (void)
+{
+  size_t leny = strlen (ay);
+  return leny;
+}
+
+int cmp88 (void)
+{
+  int cmp88 = memcmp (a8, "1234567\0", sizeof a8);
+  return cmp88;
+}
+
+/* { dg-final { scan-tree-dump-times "strlen" 0 "gimple" } }
+   { dg-final { scan-tree-dump-times "len0 = 0;" 1 "gimple" } }
+   { dg-final { scan-tree-dump-times "len = 18;" 1 "gimple" } }
+   { dg-final { scan-tree-dump-times "lenx = 8;" 1 "gimple" } }
+   { dg-final { scan-tree-dump-times "leny = 0;" 1 "gimple" } }
+   { dg-final { scan-tree-dump-times "cmp88 = 0;" 1 "gimple" } } */