1 files changed, 32 insertions, 0 deletions
diff --git a/lib/ctzti2.c b/lib/ctzti2.c
new file mode 100644
index 00000000..828db266
--- /dev/null
+++ b/lib/ctzti2.c
@@ -0,0 +1,32 @@
+//===-- ctzti2.c - Implement __ctzti2 -------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements __ctzti2 for the compiler_rt library.
+//
+//===----------------------------------------------------------------------===//
+
+#if __x86_64
+
+#include "int_lib.h"
+
+// Returns: the number of trailing 0-bits
+
+// Precondition: a != 0
+
+si_int
+__ctzti2(ti_int a)
+{
+    twords x;
+    x.all = a;
+    const di_int f = -(x.low == 0);
+    return __builtin_ctzll((x.high & f) | (x.low & ~f)) +
+              ((si_int)f & ((si_int)(sizeof(di_int) * CHAR_BIT)));
+}
+
+#endif