qpms/optim.h

   1 /** \file optim.h
   2  * \brief Macros for compiler optimisation.
   3  */
   4 #ifndef QPMS_OPTIM_H
   5 #define QPMS_OPTIM_H
   6
   7
   8 #if ((defined __GNUC__) || (defined __clang__)) && !(defined QPMS_NO_BUILTIN_EXPECT)
   9 /// Wrapper over gcc's and clang's __builtin_expect.
  10 /** If expands to __builtin_expect if gcc or clang are used,
  11  * else expands only to the first argument.
  12  */
  13 #define QPMS_EXPECT(exp, c) __builtin_expect(exp, c)
  14 #define QPMS_LIKELY(x) __builtin_expect(!!(x), 1)
  15 #define QPMS_UNLIKELY(x) __builtin_expect(!!(x), 0)
  16 #else
  17 #define QPMS_LIKELY(x) (x)
  18 #define QPMS_UNLIKELY(x)
  19 #define QPMS_EXPECT(exp,c) (exp)
  20 #endif
  21
  22 #if (defined(__GNUC__) && __GNUC__ >= 3) || \
  23     (defined(__GNUC__) && defined(__GNUC_MINOR__) && __GNUC__ == 2 && __GNUC_MINOR__ >= 8)
  24 // TODO clang
  25 #define QPMS_NORETURN __attribute__((noreturn))
  26 #endif
  27
  28 #endif // OPTIM_H