1 files changed, 50 insertions, 0 deletions
diff --git a/tests/src/JIT/Regression/JitBlue/DevDiv_1206929/DevDiv_1206929.cs b/tests/src/JIT/Regression/JitBlue/DevDiv_1206929/DevDiv_1206929.cs
new file mode 100644
index 0000000000..d363360272
--- /dev/null
+++ b/tests/src/JIT/Regression/JitBlue/DevDiv_1206929/DevDiv_1206929.cs
@@ -0,0 +1,50 @@
+using System;
+using System.Runtime.CompilerServices;
+
+namespace ReadMemBytes
+{
+    class Program
+    {
+        static int Pass = 100;
+        static int Fail = -1;
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        static unsafe int TestMemBytesNotReadPastTheLimit(byte *p, int byteLength)
+        {
+            int count = 0;
+            for (int i= 0; i< byteLength; ++i)
+            {
+                // RyuJIT lowering has an optimization to recognize the condition in
+                // "If" stmnt and generate "test byte ptr [p+i], 0" instruction. Due
+                // to a bug that has been fixed it will end up generating "test dword ptr [p+i], 0"
+                // that will lead to reading 4 bytes instead of a single byte.
+                if ((p[i] & 0xffffff00) != 0)
+                {
+                    ++count;
+                }
+            }
+
+            return count;
+        }
+        static unsafe int Main(string[] args)
+        {
+            byte* buffer = stackalloc byte[4];
+            buffer[0] = 0;
+            buffer[1] = buffer[2] = buffer[3] = 0xff;
+
+            int result = TestMemBytesNotReadPastTheLimit(buffer, 1);
+            if (result != 0)
+            {
+                Console.WriteLine("Failed: Read past the end of buffer");
+                return Fail;
+            }
+            else
+            {
+                Console.WriteLine("Pass");
+            }
+
+            return Pass;
+
+        }
+    }
+}