Use clz ^ 31 instead of 31 - clz; better codegen for GCC

2019-09-23 21:23:09 +02:00
parent 7451c6578c
commit 1f7228c040
8 changed files with 8 additions and 8 deletions
@@ -164,7 +164,7 @@ MEM_STATIC unsigned BIT_highbit32 (U32 val)
        _BitScanReverse ( &r, val );
        return (unsigned) r;
 #   elif defined(__GNUC__) && (__GNUC__ >= 3)   /* Use GCC Intrinsic */
-        return 31 - __builtin_clz (val);
+        return __builtin_clz (val) ^ 31;
 #   elif defined(__ICCARM__)    /* IAR Intrinsic */
        return 31 - __CLZ(val);
 #   else   /* Software version */