From 75588b6ed2692b86b760b5390a33d380d642c925 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Sun, 6 Oct 2013 23:43:43 -0700 Subject: [PATCH] count-one-bits: port to MSC; support types wider than 64 bits The ideas behind the MSC port are stolen from Emacs. * lib/count-one-bits.c (popcount_support) [_MSC_VER]: New variable. * lib/count-one-bits.h: Include limits.h, for CHAR_BIT. Don't include verify.h: it's no longer needed, as types wider than 64 bits are now supported. (COUNT_ONE_BITS_GENERIC): New macro. (popcount_supported) [_MSC_VER]: New inline function. (COUNT_ONE_BITS): Use it. New arg MSC_BUILTIN, for better performance with MSC. All uses changed. Do not assume that TYPE has at most 64 bits. * modules/count-one-bits (Depends-on): Do not depend on 'verify'. --- ChangeLog | 15 +++++++++ lib/count-one-bits.c | 4 +++ lib/count-one-bits.h | 83 +++++++++++++++++++++++++++++++++++++++----------- modules/count-one-bits | 1 - 4 files changed, 85 insertions(+), 18 deletions(-) diff --git a/ChangeLog b/ChangeLog index 582d6e08c..3d4f38d29 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,18 @@ +2013-10-06 Paul Eggert + + count-one-bits: port to MSC; support types wider than 64 bits + The ideas behind the MSC port are stolen from Emacs. + * lib/count-one-bits.c (popcount_support) [_MSC_VER]: New variable. + * lib/count-one-bits.h: Include limits.h, for CHAR_BIT. + Don't include verify.h: it's no longer needed, as types wider than + 64 bits are now supported. + (COUNT_ONE_BITS_GENERIC): New macro. + (popcount_supported) [_MSC_VER]: New inline function. + (COUNT_ONE_BITS): Use it. New arg MSC_BUILTIN, for better + performance with MSC. All uses changed. Do not assume that TYPE + has at most 64 bits. + * modules/count-one-bits (Depends-on): Do not depend on 'verify'. + 2013-10-06 Andrew Borodin mountlist: fix resource leak with MOUNTED_INTERIX_STATVFS diff --git a/lib/count-one-bits.c b/lib/count-one-bits.c index b15aec489..66341d77c 100644 --- a/lib/count-one-bits.c +++ b/lib/count-one-bits.c @@ -1,3 +1,7 @@ #include #define COUNT_ONE_BITS_INLINE _GL_EXTERN_INLINE #include "count-one-bits.h" + +#if 1500 <= _MSC_VER && (defined _M_IX86 || defined _M_X64) +int popcount_support = -1; +#endif diff --git a/lib/count-one-bits.h b/lib/count-one-bits.h index ce9d67ecb..2a7e93c3f 100644 --- a/lib/count-one-bits.h +++ b/lib/count-one-bits.h @@ -17,10 +17,10 @@ /* Written by Ben Pfaff. */ #ifndef COUNT_ONE_BITS_H -# define COUNT_ONE_BITS_H 1 +#define COUNT_ONE_BITS_H 1 +#include #include -#include "verify.h" #ifndef _GL_INLINE_HEADER_BEGIN #error "Please include config.h first." @@ -30,21 +30,30 @@ _GL_INLINE_HEADER_BEGIN # define COUNT_ONE_BITS_INLINE _GL_INLINE #endif -/* Expand the code which computes the number of 1-bits of the local - variable 'x' of type TYPE (an unsigned integer type) and returns it +/* 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) + +/* Assuming the GCC builtin is 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, TYPE) \ - return BUILTIN (x); +# define COUNT_ONE_BITS(BUILTIN, MSC_BUILTIN, TYPE) return BUILTIN (x) #else -#define COUNT_ONE_BITS(BUILTIN, TYPE) \ - /* This condition is written so as to avoid shifting by more than \ - 31 bits at once, and also avoids a random HP-UX cc bug. */ \ - verify (((TYPE) -1 >> 31 >> 31 >> 2) == 0); /* TYPE has at most 64 bits */ \ - int count = count_one_bits_32 (x); \ - if (1 < (TYPE) -1 >> 31) /* TYPE has more than 32 bits? */ \ - count += count_one_bits_32 (x >> 31 >> 1); \ - return count; /* Compute and return the number of 1-bits set in the least significant 32 bits of X. */ @@ -57,20 +66,60 @@ count_one_bits_32 (unsigned int x) x = ((x & 0xf0f0) >> 4) + (x & 0x0f0f); return (x >> 8) + (x & 0x00ff); } + +# 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 + +/* Return nonzero if popcount is supported. */ + +/* 1 if supported, 0 if not supported, -1 if unknown. */ +extern int popcount_support; + +COUNT_ONE_BITS_INLINE int +popcount_supported (void) +{ + if (popcount_support < 0) + { + int cpu_info[4]; + __cpuid (cpu_info, 1); + popcount_support = (cpu_info[2] >> 23) & 1; /* See MSDN. */ + } + 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); \ + } \ + while (0) +# else +# define COUNT_ONE_BITS(BUILTIN, MSC_BUILTIN, TYPE) \ + COUNT_ONE_BITS_GENERIC (TYPE) +# endif #endif /* Compute and return the number of 1-bits set in X. */ COUNT_ONE_BITS_INLINE int count_one_bits (unsigned int x) { - COUNT_ONE_BITS (__builtin_popcount, unsigned int); + COUNT_ONE_BITS (__builtin_popcount, __popcnt, unsigned int); } /* Compute and return the number of 1-bits set in X. */ COUNT_ONE_BITS_INLINE int count_one_bits_l (unsigned long int x) { - COUNT_ONE_BITS (__builtin_popcountl, unsigned long int); + COUNT_ONE_BITS (__builtin_popcountl, __popcnt, unsigned long int); } #if HAVE_UNSIGNED_LONG_LONG_INT @@ -78,7 +127,7 @@ count_one_bits_l (unsigned long int x) COUNT_ONE_BITS_INLINE int count_one_bits_ll (unsigned long long int x) { - COUNT_ONE_BITS (__builtin_popcountll, unsigned long long int); + COUNT_ONE_BITS (__builtin_popcountll, __popcnt64, unsigned long long int); } #endif diff --git a/modules/count-one-bits b/modules/count-one-bits index 3922d85f8..7bb18bd76 100644 --- a/modules/count-one-bits +++ b/modules/count-one-bits @@ -8,7 +8,6 @@ m4/count-one-bits.m4 Depends-on: extern-inline -verify configure.ac: gl_COUNT_ONE_BITS -- 2.11.0