1 files changed, 34 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/pr20204.c b/gcc/testsuite/gcc.dg/pr20204.c
new file mode 100644
index 00000000000..ad85af5baa3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr20204.c
@@ -0,0 +1,34 @@
+/* { dg-do run { target i?86-*-* } } */
+/* { dg-options "-O2" } */
+
+void *x (void *pdst, const void *psrc, unsigned int pn)
+{
+  register void *return_dst = pdst;
+  register unsigned char *dst = pdst;
+  register unsigned const char *src = psrc;
+  register int n __asm__ ("ebx") = pn;
+
+  if (src < dst && dst < src + n)
+    {
+      src += n;
+      dst += n;
+      while (n--)
+        *--dst = *--src;
+      return return_dst;
+    }
+
+  while (n >= 16) n--;
+
+  return return_dst;
+}
+extern void abort ();
+extern void exit (int);
+char xx[30] = "abc";
+int main (void)
+{
+  char yy[30] = "aab";
+
+  if (x (xx + 1, xx, 2) != xx + 1 || memcmp (xx, yy, sizeof (yy)) != 0)
+    abort ();
+  exit (0);
+}