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Don't define the MSVC clz functions unless __builtin_clzll is unavailable.

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This is mainly just to avoid including intrin.h unnecessarily.
This commit is contained in:
Michael Winterberg 2016-01-07 15:19:27 -08:00
parent 28a303ddd4
commit b203beb61d
1 changed files with 16 additions and 21 deletions
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15
format.h
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@ -225,16 +225,15 @@ typedef __int64 intmax_t;
# define FMT_BUILTIN_CLZLL(n) __builtin_clzll(n)
#endif
#if defined(_MSC_VER)
# include <intrin.h> // _BitScanReverse, _BitScanReverse64
namespace fmt {
namespace internal {
// Some compilers masquerade as both MSVC and GCC-likes or
// otherwise support __builtin_clz and __builtin_clzll, so
// only define FMT_BUILTIN_CLZ using the MSVC intrinsics
// if the clz and clzll builtins are not available.
# if !defined(FMT_BUILTIN_CLZ)
#if defined(_MSC_VER) && !defined(FMT_BUILTIN_CLZLL)
# include <intrin.h> // _BitScanReverse, _BitScanReverse64
namespace fmt {
namespace internal {
# pragma intrinsic(_BitScanReverse)
inline uint32_t clz(uint32_t x) {
unsigned long r = 0;
@ -248,10 +247,7 @@ inline uint32_t clz(uint32_t x) {
return 31 - r;
}
# define FMT_BUILTIN_CLZ(n) fmt::internal::clz(n)
# endif
# if !defined(FMT_BUILTIN_CLZLL)
# pragma intrinsic(_BitScanReverse)
# ifdef _WIN64
# pragma intrinsic(_BitScanReverse64)
# endif
@ -277,7 +273,6 @@ inline uint32_t clzll(uint64_t x) {
return 63 - r;
}
# define FMT_BUILTIN_CLZLL(n) fmt::internal::clzll(n)
# endif
}
}
#endif