Import libcompiler_rt into HEAD and add Makefiles.

Obtained from:	user/ed/compiler-rt

1 files changed, 41 insertions, 0 deletions

diff --git a/contrib/compiler-rt/lib/subvti3.c b/contrib/compiler-rt/lib/subvti3.c
new file mode 100644
index 0000000..55b7925
--- /dev/null
+++ b/contrib/compiler-rt/lib/subvti3.c
@@ -0,0 +1,41 @@
+/* ===-- 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)
+            compilerrt_abort();
+    }
+    else
+    {
+        if (s <= a)
+            compilerrt_abort();
+    }
+    return s;
+}
+
+#endif /* __x86_64 */