--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/strlenopt-9.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,107 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fno-code-hoisting -fdump-tree-strlen -fdump-tree-optimized" } */
+
+#include "strlenopt.h"
+
+__attribute__((noinline, noclone)) char *
+fn1 (int r)
+{
+  char *p = r ? "a" : "bc";
+  /* String length for p varies, therefore strchr below isn't
+     optimized away.  */
+  return strchr (p, '\0');
+}
+
+__attribute__((noinline, noclone)) size_t
+fn2 (int r)
+{
+  char *p, q[10];
+  strcpy (q, "abc");
+  p = r ? "a" : q;
+  /* String length is constant for both alternatives, and strlen is
+     optimized away.  */
+  return strlen (p);
+}
+
+__attribute__((noinline, noclone)) size_t
+fn3 (char *p, int n)
+{
+  int i;
+  p = strchr (p, '\0');
+  /* strcat here can be optimized into memcpy.  */
+  strcat (p, "abcd");
+  for (i = 0; i < n; i++)
+    if ((i % 123) == 53)
+      /* strcat here is optimized into strlen and memcpy.  */
+      strcat (p, "efg");
+  /* The strlen here can't be optimized away, as in the loop string
+     length of p might change.  */
+  return strlen (p);
+}
+
+char buf[64];
+
+__attribute__((noinline, noclone)) size_t
+fn4 (char *x, int n)
+{
+  int i;
+  size_t l;
+  char a[64];
+  char *p = strchr (x, '\0');
+  /* strcpy here is optimized into memcpy, length computed as p - x + 1.  */
+  strcpy (a, x);
+  /* strcat here is optimized into memcpy.  */
+  strcat (p, "abcd");
+  for (i = 0; i < n; i++)
+    if ((i % 123) == 53)
+      /* strcat here is optimized into strlen and memcpy.  */
+      strcat (a, "efg");
+  /* The strlen should be optimized here into 4.  */
+  l = strlen (p);
+  /* This stays strcpy.  */
+  strcpy (buf, a);
+  return l;
+}
+
+int
+main ()
+{
+  volatile int l = 1;
+  char b[64];
+
+  if (memcmp (fn1 (l) - 1, "a", 2) != 0)
+    abort ();
+  if (memcmp (fn1 (!l) - 2, "bc", 3) != 0)
+    abort ();
+  if (fn2 (l) != 1 || fn2 (!l) != 3)
+    abort ();
+  memset (b, '\0', sizeof b);
+  memset (b, 'a', 3);
+  if (fn3 (b, 10) != 4 || memcmp (b, "aaaabcd", 8) != 0)
+    abort ();
+  if (fn3 (b, 128) != 7 || memcmp (b, "aaaabcdabcdefg", 15) != 0)
+    abort ();
+  if (fn3 (b, 256) != 10 || memcmp (b, "aaaabcdabcdefgabcdefgefg", 25) != 0)
+    abort ();
+  if (fn4 (b, 10) != 4
+      || memcmp (b, "aaaabcdabcdefgabcdefgefgabcd", 29) != 0
+      || memcmp (buf, "aaaabcdabcdefgabcdefgefg", 25) != 0)
+    abort ();
+  if (fn4 (b, 128) != 4
+      || memcmp (b, "aaaabcdabcdefgabcdefgefgabcdabcd", 33) != 0
+      || memcmp (buf, "aaaabcdabcdefgabcdefgefgabcdefg", 32) != 0)
+    abort ();
+  if (fn4 (b, 256) != 4
+      || memcmp (b, "aaaabcdabcdefgabcdefgefgabcdabcdabcd", 37) != 0
+      || memcmp (buf, "aaaabcdabcdefgabcdefgefgabcdabcdefgefg", 39) != 0)
+    abort ();
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "strlen \\(" 5 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "memcpy \\(" 6 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strcpy \\(" 1 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strcat \\(" 0 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strchr \\(" 0 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "stpcpy \\(" 0 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "return 4;" 1 "optimized" } } */