Don't initialize the first parameter of _BitScanReverse* functions

Like the document example, no need to initialize `r` to 0. https://docs.microsoft.com/en-us/cpp/intrinsics/bitscanreverse-bitscanreverse64
2021-09-25 16:36:53 +08:00
parent cc22042da0
commit 95f492ea17
11 changed files with 21 additions and 30 deletions
@@ -530,9 +530,8 @@ MEM_STATIC size_t BITv07_readBitsFast(BITv07_DStream_t* bitD, unsigned nbBits);
 MEM_STATIC unsigned BITv07_highbit32 (U32 val)
 {
 #   if defined(_MSC_VER)   /* Visual */
-    unsigned long r=0;
-    _BitScanReverse ( &r, val );
-    return (unsigned) r;
+    unsigned long r;
+    return _BitScanReverse(&r, val) ? (unsigned)r : 0;
 #   elif defined(__GNUC__) && (__GNUC__ >= 3)   /* Use GCC Intrinsic */
    return __builtin_clz (val) ^ 31;
 #   else   /* Software version */