Don't initialize the first parameter of _BitScanForward* functions

Like the document example, no need to initialize `r` to 0.
https://docs.microsoft.com/en-us/cpp/intrinsics/bitscanforward-bitscanforward64

diff --git a/lib/common/entropy_common.c b/lib/common/entropy_common.c
index 6ba1f2209af84a12cf0e9b3265ff17abea41eb79..dd80b2cccb9e9387bbc2079858593c85a24cc734 100644 (file)
--- a/lib/common/entropy_common.c
+++ b/lib/common/entropy_common.c
@@ -43,7 +43,7 @@ static U32 FSE_ctz(U32 val)
     assert(val != 0);
     {
 #   if defined(_MSC_VER)   /* Visual */
-        unsigned long r=0;
+        unsigned long r;
         return _BitScanForward(&r, val) ? (unsigned)r : 0;
 #   elif defined(__GNUC__) && (__GNUC__ >= 3)   /* GCC Intrinsic */
         return __builtin_ctz(val);

diff --git a/lib/common/zstd_internal.h b/lib/common/zstd_internal.h
index ba1b7bbc8bae9f170c3d30e2c42d5c6512af5782..246022c5f2374c2dc08555a8882a0bc6e6bcd2ba 100644 (file)
--- a/lib/common/zstd_internal.h
+++ b/lib/common/zstd_internal.h
@@ -391,7 +391,7 @@ MEM_STATIC unsigned ZSTD_countTrailingZeros(size_t val)
 #           if STATIC_BMI2
                 return _tzcnt_u64(val);
 #           else
-                unsigned long r = 0;
+                unsigned long r;
                 return _BitScanForward64( &r, (U64)val ) ? (unsigned)(r >> 3) : 0;
 #           endif
 #       elif defined(__GNUC__) && (__GNUC__ >= 4)
@@ -409,7 +409,7 @@ MEM_STATIC unsigned ZSTD_countTrailingZeros(size_t val)
 #       endif
     } else { /* 32 bits */
 #       if defined(_MSC_VER)
-            unsigned long r=0;
+            unsigned long r;
             return _BitScanForward( &r, (U32)val ) ? (unsigned)(r >> 3) : 0;
 #       elif defined(__GNUC__) && (__GNUC__ >= 3)
             return (__builtin_ctz((U32)val) >> 3);

diff --git a/lib/compress/zstd_compress_internal.h b/lib/compress/zstd_compress_internal.h
index 6821c9df8bedcd24adefa161c8aa85cc8c1b8021..bc30daa75df7232478b7ee6c9d6744048fba7562 100644 (file)
--- a/lib/compress/zstd_compress_internal.h
+++ b/lib/compress/zstd_compress_internal.h
@@ -672,7 +672,7 @@ static unsigned ZSTD_NbCommonBytes (size_t val)
 #           if STATIC_BMI2
                 return _tzcnt_u64(val) >> 3;
 #           else
-                unsigned long r = 0;
+                unsigned long r;
                 return _BitScanForward64( &r, (U64)val ) ? (unsigned)(r >> 3) : 0;
 #           endif
 #       elif defined(__GNUC__) && (__GNUC__ >= 4)
@@ -690,7 +690,7 @@ static unsigned ZSTD_NbCommonBytes (size_t val)
 #       endif
         } else { /* 32 bits */
 #       if defined(_MSC_VER)
-            unsigned long r=0;
+            unsigned long r;
             return _BitScanForward( &r, (U32)val ) ? (unsigned)(r >> 3) : 0;
 #       elif defined(__GNUC__) && (__GNUC__ >= 3)
             return (__builtin_ctz((U32)val) >> 3);

diff --git a/lib/compress/zstd_lazy.c b/lib/compress/zstd_lazy.c
index fef28de8d81c2490396bad3f73d25ed4451f93f9..ac84b479ff7fb7e15e581ee7488caeef568f5875 100644 (file)
--- a/lib/compress/zstd_lazy.c
+++ b/lib/compress/zstd_lazy.c
@@ -882,7 +882,7 @@ static U32 ZSTD_VecMask_next(ZSTD_VecMask val) {
     assert(val != 0);
 #   if defined(_MSC_VER) && defined(_WIN64)
     {
-        unsigned long r = 0;
+        unsigned long r;
         /* _BitScanForward64 is not defined outside of x64 */
         return _BitScanForward64(&r, val) ? (U32)r : 0;
     }

diff --git a/lib/dictBuilder/zdict.c b/lib/dictBuilder/zdict.c
index 2421f40f35d6c8da9e74b237365155dc6b678714..ea00eafc7ab4597eeb648bdc7ab265992cf5a214 100644 (file)
--- a/lib/dictBuilder/zdict.c
+++ b/lib/dictBuilder/zdict.c
@@ -135,9 +135,8 @@ static unsigned ZDICT_NbCommonBytes (size_t val)
     if (MEM_isLittleEndian()) {
         if (MEM_64bits()) {
 #       if defined(_MSC_VER) && defined(_WIN64)
-            unsigned long r = 0;
-            _BitScanForward64( &r, (U64)val );
-            return (unsigned)(r>>3);
+            unsigned long r;
+            return _BitScanForward64(&r, (U64)val) ? (unsigned)(r >> 3) : 0;
 #       elif defined(__GNUC__) && (__GNUC__ >= 3)
             return (unsigned)(__builtin_ctzll((U64)val) >> 3);
 #       else
@@ -146,9 +145,8 @@ static unsigned ZDICT_NbCommonBytes (size_t val)
 #       endif
         } else { /* 32 bits */
 #       if defined(_MSC_VER)
-            unsigned long r=0;
-            _BitScanForward( &r, (U32)val );
-            return (unsigned)(r>>3);
+            unsigned long r;
+            return _BitScanForward(&r, (U32)val) ? (unsigned)(r >> 3) : 0;
 #       elif defined(__GNUC__) && (__GNUC__ >= 3)
             return (unsigned)(__builtin_ctz((U32)val) >> 3);
 #       else