1 files changed, 37 insertions, 0 deletions
diff --git a/lib/builtins/ffsti2.c b/lib/builtins/ffsti2.c
new file mode 100644
index 000000000000..dcdb3bd7f807
--- /dev/null
+++ b/lib/builtins/ffsti2.c
@@ -0,0 +1,37 @@
+/* ===-- ffsti2.c - Implement __ffsti2 -------------------------------------===
+ *
+ *                     The LLVM Compiler Infrastructure
+ *
+ * This file is dual licensed under the MIT and the University of Illinois Open
+ * Source Licenses. See LICENSE.TXT for details.
+ *
+ * ===----------------------------------------------------------------------===
+ *
+ * This file implements __ffsti2 for the compiler_rt library.
+ *
+ * ===----------------------------------------------------------------------===
+ */
+
+#include "int_lib.h"
+
+#ifdef CRT_HAS_128BIT
+
+/* Returns: the index of the least significant 1-bit in a, or
+ * the value zero if a is zero. The least significant bit is index one.
+ */
+
+COMPILER_RT_ABI si_int
+__ffsti2(ti_int a)
+{
+    twords x;
+    x.all = a;
+    if (x.s.low == 0)
+    {
+        if (x.s.high == 0)
+            return 0;
+        return __builtin_ctzll(x.s.high) + (1 + sizeof(di_int) * CHAR_BIT);
+    }
+    return __builtin_ctzll(x.s.low) + 1;
+}
+
+#endif /* CRT_HAS_128BIT */