--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp18.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,33 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-vrp1" } */
+
+static int blocksize = 4096;
+
+int bar (int);
+
+void foo (void)
+{
+  int toread;
+  int bytes;
+  static char eof_reached = 0;
+
+  toread = blocksize;
+  bytes = 1;
+
+  while (toread != 0)
+    {
+      bytes = bar (toread);
+      if (bytes <= 0)
+        {
+          if (bytes < 0)
+            continue;
+          break;
+        }
+      toread -= bytes;
+    }
+
+  if (bytes == 0)
+    eof_reached = 1;
+}
+
+/* { dg-final { scan-tree-dump-times "Simplified relational" 1 "vrp1" } } */