1 files changed, 40 insertions, 0 deletions
diff --git a/lib/subvti3.c b/lib/subvti3.c
new file mode 100644
index 000000000..b130c8ceb
--- /dev/null
+++ b/lib/subvti3.c
@@ -0,0 +1,40 @@
+//===-- subvti3.c - Implement __subvti3 -----------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements __subvti3 for the compiler_rt library.
+//
+//===----------------------------------------------------------------------===//
+
+#if __x86_64
+
+#include "int_lib.h"
+#include <stdlib.h>
+
+// Returns: a - b
+
+// Effects: aborts if a - b overflows
+
+ti_int
+__subvti3(ti_int a, ti_int b)
+{
+    ti_int s = a - b;
+    if (b >= 0)
+    {
+        if (s > a)
+            abort();
+    }
+    else
+    {
+        if (s <= a)
+            abort();
+    }
+    return s;
+}
+
+#endif