Import libcompiler_rt into HEAD and add Makefiles.

Obtained from:	user/ed/compiler-rt

1 files changed, 30 insertions, 0 deletions

diff --git a/contrib/compiler-rt/lib/absvsi2.c b/contrib/compiler-rt/lib/absvsi2.c
new file mode 100644
index 0000000..a2c8e3f
--- /dev/null
+++ b/contrib/compiler-rt/lib/absvsi2.c
@@ -0,0 +1,30 @@
+/* ===-- absvsi2.c - Implement __absvsi2 -----------------------------------===
+ *
+ *                     The LLVM Compiler Infrastructure
+ *
+ * This file is distributed under the University of Illinois Open Source
+ * License. See LICENSE.TXT for details.
+ *
+ * ===----------------------------------------------------------------------===
+ *
+ * This file implements __absvsi2 for the compiler_rt library.
+ *
+ * ===----------------------------------------------------------------------===
+ */ 
+
+#include "int_lib.h"
+#include <stdlib.h>
+
+/* Returns: absolute value */
+
+/* Effects: aborts if abs(x) < 0 */
+
+si_int
+__absvsi2(si_int a)
+{
+    const int N = (int)(sizeof(si_int) * CHAR_BIT);
+    if (a == (1 << (N-1)))
+        compilerrt_abort();
+    const si_int t = a >> (N - 1);
+    return (a ^ t) - t;
+}