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      1 /*
      2  * Copyright (c) Meta Platforms, Inc. and affiliates.
      3  * All rights reserved.
      4  *
      5  * This source code is licensed under both the BSD-style license (found in the
      6  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
      7  * in the COPYING file in the root directory of this source tree).
      8  */
      9 
     10 /**
     11  * Compiler hints to indicate the fast path of an "if" branch: whether
     12  * the if condition is likely to be true or false.
     13  *
     14  * @author Tudor Bosman (tudorb (at) fb.com)
     15  */
     16 
     17 #pragma once
     18 
     19 #undef LIKELY
     20 #undef UNLIKELY
     21 
     22 #if defined(__GNUC__) && __GNUC__ >= 4
     23 #define LIKELY(x) (__builtin_expect((x), 1))
     24 #define UNLIKELY(x) (__builtin_expect((x), 0))
     25 #else
     26 #define LIKELY(x) (x)
     27 #define UNLIKELY(x) (x)
     28 #endif
     29