diff --git a/sdefl.h b/sdefl.h
index 5d5bcd0..1aa8d18 100644
--- a/sdefl.h
+++ b/sdefl.h
@@ -202,7 +202,7 @@ extern "C" {
 static int
 sdefl_ilog2(int n) {
   if (!n) return 0;
-#ifdef _MSC_VER
+#if defined(_MSC_VER) && !defined(__clang__)
   unsigned long msbp = 0;
   _BitScanReverse(&msbp, (unsigned long)n);
   return (int)msbp;
diff --git a/sinfl.h b/sinfl.h
index 3f60e88..9885baf 100644
--- a/sinfl.h
+++ b/sinfl.h
@@ -174,7 +174,7 @@ extern "C" {
 
 static int
 sinfl_bsr(unsigned long n) {
-#ifdef _MSC_VER
+#if defined(_MSC_VER) && !defined(__clang__)
   unsigned long r = 0;
   _BitScanReverse(&r, n);
   return (int)(r);