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authorakr <akr@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2013-07-15 01:49:32 +0000
committerakr <akr@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2013-07-15 01:49:32 +0000
commit150b2655024892d48ca6af5f70731e2ab68a491f (patch)
treec15501a03f21e41fb5ab837d7dc1bb4bf10f2fec
parent0e15aec62b15627a209cbfbae5d1f20391d74b4b (diff)
* 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. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41976 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
-rw-r--r--ChangeLog10
-rw-r--r--bignum.c26
-rw-r--r--configure.in3
3 files changed, 39 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog
index 3be2ca8e1c5..299b5ccae25 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -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.
diff --git a/bignum.c b/bignum.c
index fa8477e8219..ca98c44837e 100644
--- a/bignum.c
+++ b/bignum.c
@@ -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
diff --git a/configure.in b/configure.in
index 739d3370726..48184e23cf5 100644
--- a/configure.in
+++ b/configure.in
@@ -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