diff --git a/src/libFLAC/bitmath.c b/src/libFLAC/bitmath.c
index b9e8e85d..64b5eca3 100644
--- a/src/libFLAC/bitmath.c
+++ b/src/libFLAC/bitmath.c
@@ -35,7 +35,6 @@
 #endif
 
 #include "private/bitmath.h"
-#include "FLAC/assert.h"
 
 /* An example of what FLAC__bitmath_silog2() computes:
  *
diff --git a/src/libFLAC/include/private/bitmath.h b/src/libFLAC/include/private/bitmath.h
index fd65cca5..ae303147 100644
--- a/src/libFLAC/include/private/bitmath.h
+++ b/src/libFLAC/include/private/bitmath.h
@@ -34,6 +34,7 @@
 #define FLAC__PRIVATE__BITMATH_H
 
 #include "FLAC/ordinals.h"
+#include "FLAC/assert.h"
 
 /* for CHAR_BIT */
 #include <limits.h>
@@ -74,6 +75,7 @@ static inline unsigned int FLAC__clz_soft_uint32(unsigned int word)
 static inline unsigned int FLAC__clz_uint32(FLAC__uint32 v)
 {
 /* Never used with input 0 */
+    FLAC__ASSERT(v > 0);
 #if defined(__INTEL_COMPILER)
     return _bit_scan_reverse(v) ^ 31U;
 #elif defined(__GNUC__) && (__GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
@@ -81,9 +83,11 @@ static inline unsigned int FLAC__clz_uint32(FLAC__uint32 v)
  * -march= setting or to a software routine in exotic machines. */
     return __builtin_clz(v);
 #elif defined(_MSC_VER) && (_MSC_VER >= 1400)
-    unsigned long idx;
-    _BitScanReverse(&idx, v);
-    return idx ^ 31U;
+    {
+        unsigned long idx;
+        _BitScanReverse(&idx, v);
+        return idx ^ 31U;
+    }
 #else
     return FLAC__clz_soft_uint32(v);
 #endif
@@ -99,7 +103,7 @@ static inline unsigned int FLAC__clz2_uint32(FLAC__uint32 v)
 
 /* An example of what FLAC__bitmath_ilog2() computes:
  *
- * ilog2( 0) = undefined
+ * ilog2( 0) = assertion failure
  * ilog2( 1) = 0
  * ilog2( 2) = 1
  * ilog2( 3) = 1
@@ -122,12 +126,15 @@ static inline unsigned int FLAC__clz2_uint32(FLAC__uint32 v)
 
 static inline unsigned FLAC__bitmath_ilog2(FLAC__uint32 v)
 {
+    FLAC__ASSERT(v > 0);
 #if defined(__INTEL_COMPILER)
     return _bit_scan_reverse(v);
 #elif defined(_MSC_VER) && (_MSC_VER >= 1400)
-    unsigned long idx;
-    _BitScanReverse(&idx, v);
-    return idx;
+    {
+        unsigned long idx;
+        _BitScanReverse(&idx, v);
+        return idx;
+    }
 #else
     return sizeof(FLAC__uint32) * CHAR_BIT  - 1 - FLAC__clz_uint32(v);
 #endif
@@ -138,8 +145,7 @@ static inline unsigned FLAC__bitmath_ilog2(FLAC__uint32 v)
 
 static inline unsigned FLAC__bitmath_ilog2_wide(FLAC__uint64 v)
 {
-    if (v == 0)
-		return 0;
+    FLAC__ASSERT(v > 0);
 #if defined(__GNUC__) && (__GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
     return sizeof(FLAC__uint64) * CHAR_BIT - 1 - __builtin_clzll(v);
 /* Sorry, only supported in x64/Itanium.. and both have fast FPU which makes integer-only encoder pointless */
@@ -150,7 +156,7 @@ static inline unsigned FLAC__bitmath_ilog2_wide(FLAC__uint64 v)
         return idx;
     }
 #else
-/* Brain-damaged compilers will use the fastest possible way that is,
+/*  Brain-damaged compilers will use the fastest possible way that is,
     de Bruijn sequences (http://supertech.csail.mit.edu/papers/debruijn.pdf)
     (C) Timothy B. Terriberry (tterribe@xiph.org) 2001-2009 CC0 (Public domain).
 */