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+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+// Regression test for insufficient guard on inference of initial values
+// of induction variables.
+using System.Numerics;
+
+namespace N
+{
+    public static class C
+    {
+        public static int Main(string[] args)
+        {
+            int x = 0;
+
+            // When bottom-testing sees this loop, it (questionably for performance,
+            // but correctly) copies only the first part of the disjunctive loop condition
+            // so we get
+            //
+            // B1: i = Count                // initialization
+            // B2: if (i < Count) goto B6   // duplicated loop condition (note the "zero trip" case goes to the 2nd loop condition disjunct)
+            // B3: x += i                   // loop body
+            // B4: ++i                      // increment
+            // B5: if (i < Count) goto B3   // first disjunct of loop condition
+            // B6: if (i < 20) goto B3      // second disjunct of loop condition
+            // B7: return x - 84            // post-loop
+            //
+            // At which point B3..B6 is an irreducible loop, but B3..B5 is a natural loop.
+            // This is a regression test for a bug where optRecordLoop would incorrectly
+            // identify B1 as the initial value of loop B3..B5 -- this is incorrect because
+            // the edge from B6 to B3 enters the loop with different values of i.
+            //
+            // The testcase is intentionally structured so that loop unrolling will try
+            // to unroll loop B3..B5 and generate incorrect code due to the incorrect
+            // initial value.
+            for (int i = Vector<int>.Count; i < Vector<int>.Count || i < 20; ++i)
+            {
+                x += i;
+            }
+
+            // After running the loop above, the value of x should be (Count + 19) * (20 - Count) / 2.
+            // Return 100 + x - (expected x) so the test will return 100 on success.
+            return 100 + x - ((Vector<int>.Count + 19) * (20 - Vector<int>.Count) / 2);
+        }
+    }
+}