diff options
Diffstat (limited to 'lib/count-one-bits.h')
| -rw-r--r-- | lib/count-one-bits.h | 94 |
1 files changed, 61 insertions, 33 deletions
diff --git a/lib/count-one-bits.h b/lib/count-one-bits.h index 040776f7466..a9e166aed8c 100644 --- a/lib/count-one-bits.h +++ b/lib/count-one-bits.h @@ -30,29 +30,18 @@ _GL_INLINE_HEADER_BEGIN # define COUNT_ONE_BITS_INLINE _GL_INLINE #endif -/* Expand to code that computes the number of 1-bits of the local - variable 'x' of type TYPE (an unsigned integer type) and return it - from the current function. */ -#define COUNT_ONE_BITS_GENERIC(TYPE) \ - do \ - { \ - int count = 0; \ - int bits; \ - for (bits = 0; bits < sizeof (TYPE) * CHAR_BIT; bits += 32) \ - { \ - count += count_one_bits_32 (x); \ - x = x >> 31 >> 1; \ - } \ - return count; \ - } \ - while (0) +#ifdef __cplusplus +extern "C" { +#endif -/* Assuming the GCC builtin is BUILTIN and the MSC builtin is MSC_BUILTIN, +/* Assuming the GCC builtin is GCC_BUILTIN and the MSC builtin is MSC_BUILTIN, expand to code that computes the number of 1-bits of the local variable 'x' of type TYPE (an unsigned integer type) and return it from the current function. */ -#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) -# define COUNT_ONE_BITS(BUILTIN, MSC_BUILTIN, TYPE) return BUILTIN (x) +#if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)) \ + || (__clang_major__ >= 4) +# define COUNT_ONE_BITS(GCC_BUILTIN, MSC_BUILTIN, TYPE) \ + return GCC_BUILTIN (x) #else /* Compute and return the number of 1-bits set in the least @@ -67,14 +56,46 @@ count_one_bits_32 (unsigned int x) return (x >> 8) + (x & 0x00ff); } +/* Expand to code that computes the number of 1-bits of the local + variable 'x' of type TYPE (an unsigned integer type) and return it + from the current function. */ +# define COUNT_ONE_BITS_GENERIC(TYPE) \ + do \ + { \ + int count = 0; \ + int bits; \ + for (bits = 0; bits < sizeof (TYPE) * CHAR_BIT; bits += 32) \ + { \ + count += count_one_bits_32 (x); \ + x = x >> 31 >> 1; \ + } \ + return count; \ + } \ + while (0) + # if 1500 <= _MSC_VER && (defined _M_IX86 || defined _M_X64) /* While gcc falls back to its own generic code if the machine on which it's running doesn't support popcount, with Microsoft's compiler we need to detect and fallback ourselves. */ -# pragma intrinsic __cpuid -# pragma intrinsic __popcnt -# pragma intrinsic __popcnt64 + +# if 0 +# include <intrin.h> +# else + /* Don't pollute the namespace with too many MSVC intrinsics. */ +# pragma intrinsic (__cpuid) +# pragma intrinsic (__popcnt) +# if defined _M_X64 +# pragma intrinsic (__popcnt64) +# endif +# endif + +# if !defined _M_X64 +static inline __popcnt64 (unsigned long long x) +{ + return __popcnt ((unsigned int) (x >> 32)) + __popcnt ((unsigned int) x); +} +# endif /* Return nonzero if popcount is supported. */ @@ -86,25 +107,30 @@ popcount_supported (void) { if (popcount_support < 0) { + /* Do as described in + <https://docs.microsoft.com/en-us/cpp/intrinsics/popcnt16-popcnt-popcnt64> */ int cpu_info[4]; __cpuid (cpu_info, 1); - popcount_support = (cpu_info[2] >> 23) & 1; /* See MSDN. */ + popcount_support = (cpu_info[2] >> 23) & 1; } return popcount_support; } -# define COUNT_ONE_BITS(BUILTIN, MSC_BUILTIN, TYPE) \ - do \ - { \ - if (popcount_supported ()) \ - return MSC_BUILTIN (x); \ - else \ - COUNT_ONE_BITS_GENERIC (TYPE); \ - } \ +# define COUNT_ONE_BITS(GCC_BUILTIN, MSC_BUILTIN, TYPE) \ + do \ + { \ + if (popcount_supported ()) \ + return MSC_BUILTIN (x); \ + else \ + COUNT_ONE_BITS_GENERIC (TYPE); \ + } \ while (0) + # else -# define COUNT_ONE_BITS(BUILTIN, MSC_BUILTIN, TYPE) \ + +# define COUNT_ONE_BITS(GCC_BUILTIN, MSC_BUILTIN, TYPE) \ COUNT_ONE_BITS_GENERIC (TYPE) + # endif #endif @@ -122,13 +148,15 @@ count_one_bits_l (unsigned long int x) COUNT_ONE_BITS (__builtin_popcountl, __popcnt, unsigned long int); } -#if HAVE_UNSIGNED_LONG_LONG_INT /* Compute and return the number of 1-bits set in X. */ COUNT_ONE_BITS_INLINE int count_one_bits_ll (unsigned long long int x) { COUNT_ONE_BITS (__builtin_popcountll, __popcnt64, unsigned long long int); } + +#ifdef __cplusplus +} #endif _GL_INLINE_HEADER_END |