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* bignum.c (nlz16): Use __builtin_clz if possible.

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(nlz32): Use __builtin_clz or __builtin_clzl if possible.
  (nlz64): Use __builtin_clzl or __builtin_clzll if possible.
  (nlz128): Use __builtin_clzll if possible.

* configure.in: Check __builtin_clz, __builtin_clzl and
  __builtin_clzll.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41976 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
akr 2013-07-15 01:49:32 +00:00
parent 0e15aec62b
commit 150b265502
3 changed files with 39 additions and 0 deletions
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10
ChangeLog
View file

@ -1,3 +1,13 @@
Mon Jul 15 10:45:09 2013 Tanaka Akira <akr@fsij.org>
* bignum.c (nlz16): Use __builtin_clz if possible.
(nlz32): Use __builtin_clz or __builtin_clzl if possible.
(nlz64): Use __builtin_clzl or __builtin_clzll if possible.
(nlz128): Use __builtin_clzll if possible.
* configure.in: Check __builtin_clz, __builtin_clzl and
__builtin_clzll.
Mon Jul 15 09:39:07 2013 Tanaka Akira <akr@fsij.org>
* bignum.c (power_cache_get_power): Use bitsize instead of ceil_log2.

26
bignum.c
View file

@ -123,6 +123,10 @@ static void bigdivmod(VALUE x, VALUE y, volatile VALUE *divp, volatile VALUE *mo
static int
nlz16(uint16_t x)
{
#if defined(HAVE_BUILTIN___BUILTIN_CLZ) && 2 <= SIZEOF_INT
if (x == 0) return 16;
return __builtin_clz(x) - (SIZEOF_INT-2)*CHAR_BIT;
#else
uint16_t y;
int n = 16;
y = x >> 8; if (y) {n -= 8; x = y;}
@ -130,11 +134,19 @@ nlz16(uint16_t x)
y = x >> 2; if (y) {n -= 2; x = y;}
y = x >> 1; if (y) {return n - 2;}
return (int)(n - x);
#endif
}
static int
nlz32(uint32_t x)
{
#if defined(HAVE_BUILTIN___BUILTIN_CLZ) && 4 <= SIZEOF_INT
if (x == 0) return 32;
return __builtin_clz(x) - (SIZEOF_INT-4)*CHAR_BIT;
#elif defined(HAVE_BUILTIN___BUILTIN_CLZL) && 4 <= SIZEOF_LONG
if (x == 0) return 32;
return __builtin_clzl(x) - (SIZEOF_LONG-4)*CHAR_BIT;
#else
uint32_t y;
int n = 32;
y = x >> 16; if (y) {n -= 16; x = y;}
@ -143,12 +155,20 @@ nlz32(uint32_t x)
y = x >> 2; if (y) {n -= 2; x = y;}
y = x >> 1; if (y) {return n - 2;}
return (int)(n - x);
#endif
}
#if defined(HAVE_UINT64_T)
static int
nlz64(uint64_t x)
{
#if defined(HAVE_BUILTIN___BUILTIN_CLZL) && 8 <= SIZEOF_LONG
if (x == 0) return 64;
return __builtin_clzl(x) - (SIZEOF_LONG-8)*CHAR_BIT;
#elif defined(HAVE_BUILTIN___BUILTIN_CLZLL) && 8 <= SIZEOF_LONG_LONG
if (x == 0) return 64;
return __builtin_clzll(x) - (SIZEOF_LONG_LONG-8)*CHAR_BIT;
#else
uint64_t y;
int n = 64;
y = x >> 32; if (y) {n -= 32; x = y;}
@ -158,6 +178,7 @@ nlz64(uint64_t x)
y = x >> 2; if (y) {n -= 2; x = y;}
y = x >> 1; if (y) {return n - 2;}
return (int)(n - x);
#endif
}
#endif
@ -165,6 +186,10 @@ nlz64(uint64_t x)
static int
nlz128(uint128_t x)
{
#if defined(HAVE_BUILTIN___BUILTIN_CLZLL) && 16 <= SIZEOF_LONG_LONG
if (x == 0) return 128;
return __builtin_clzll(x) - (SIZEOF_LONG_LONG-16)*CHAR_BIT;
#else
uint128_t y;
int n = 128;
y = x >> 64; if (y) {n -= 64; x = y;}
@ -175,6 +200,7 @@ nlz128(uint128_t x)
y = x >> 2; if (y) {n -= 2; x = y;}
y = x >> 1; if (y) {return n - 2;}
return (int)(n - x);
#endif
}
#endif

3
configure.in
View file

@ -1849,6 +1849,9 @@ if test "${AS_TR_SH(rb_cv_builtin_$1)}" != no; then
fi])
RUBY_CHECK_BUILTIN_FUNC(__builtin_bswap32, [__builtin_bswap32(0)])
RUBY_CHECK_BUILTIN_FUNC(__builtin_bswap64, [__builtin_bswap64(0)])
RUBY_CHECK_BUILTIN_FUNC(__builtin_clz, [__builtin_clz(0)])
RUBY_CHECK_BUILTIN_FUNC(__builtin_clzl, [__builtin_clzl(0)])
RUBY_CHECK_BUILTIN_FUNC(__builtin_clzll, [__builtin_clzll(0)])
# Some platform neet -lrt for clock_gettime, but the other don't.
if test x"$ac_cv_func_clock_gettime" != xyes; then