commit 1f7228c040f614cde72ad0c48a819284f9ecd2f4
author Dávid Bolvanský <david.bolvansky@gmail.com> Mon Sep 23 21:23:09 2019 +0200
committer Dávid Bolvanský <david.bolvansky@gmail.com> Mon Sep 23 21:23:09 2019 +0200
tree a6f0045d4eb94211afa9b873b91b20e562cda8f3
parent 7451c6578c0b96cfec08f1db0428b212a6dd4389

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

lib/common/bitstream.h

diff --git a/lib/common/bitstream.h b/lib/common/bitstream.h
index 306e019..1c294b8 100644
--- a/lib/common/bitstream.h
+++ b/lib/common/bitstream.h
@@ -164,7 +164,7 @@
         _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 */