From c24912aa0f7d618307a431e53fd1f551497307f1 Mon Sep 17 00:00:00 2001
From: naruse <naruse@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Sat, 30 Apr 2016 15:39:02 +0000
Subject: * string.c (search_nonascii): unroll and use ntz

* configure.in (__builtin_ctz): check.

* configure.in (__builtin_ctzll): check.

* internal.h (rb_popcount32): defined for ntz_int32.
  it can use __builtin_popcount but this function is not used on
  GCC environment because it uses __builtin_ctz.
  When another function uses this, using __builtin_popcount
  should be re-considered.

* internal.h (rb_popcount64): ditto.

* internal.h (ntz_int32): defined for ntz_intptr.

* internal.h (ntz_int64): defined for ntz_intptr.

* internal.h (ntz_intptr): defined as ntz for uintptr_t.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@54854 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 internal.h | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

(limited to 'internal.h')

diff --git a/internal.h b/internal.h
index 7793c1ab32..a8f4240059 100644
--- a/internal.h
+++ b/internal.h
@@ -260,6 +260,52 @@ nlz_int128(uint128_t x)
 }
 #endif
 
+static inline int
+rb_popcount32(uint32_t x) {
+    x = (x & 0x55555555) + (x >> 1 & 0x55555555);
+    x = (x & 0x33333333) + (x >> 2 & 0x33333333);
+    x = (x & 0x0f0f0f0f) + (x >> 4 & 0x0f0f0f0f);
+    x = (x & 0x001f001f) + (x >> 8 & 0x001f001f);
+    return (x & 0x0000003f) + (x >>16 & 0x0000003f);
+}
+
+static inline int
+rb_popcount64(uint64_t x) {
+    x = (x & 0x5555555555555555) + (x >> 1 & 0x5555555555555555);
+    x = (x & 0x3333333333333333) + (x >> 2 & 0x3333333333333333);
+    x = (x & 0x0707070707070707) + (x >> 4 & 0x0707070707070707);
+    x = (x & 0x001f001f001f001f) + (x >> 8 & 0x001f001f001f001f);
+    x = (x & 0x0000003f0000003f) + (x >>16 & 0x0000003f0000003f);
+    return (x & 0x7f) + (x >>32 & 0x7f);
+}
+
+static inline int
+ntz_int32(uint32_t x) {
+#ifdef HAVE_BUILTIN___BUILTIN_CTZ
+    return __builtin_ctz(x);
+#else
+    return rb_popcount32((~x) & (x-1));
+#endif
+}
+
+static inline int
+ntz_int64(uint64_t x) {
+#ifdef HAVE_BUILTIN___BUILTIN_CTZLL
+    return __builtin_ctzll(x);
+#else
+    return rb_popcount64((~x) & (x-1));
+#endif
+}
+
+static inline int
+ntz_intptr(uintptr_t x) {
+#if SIZEOF_VOIDP == 8
+    return ntz_int64(x);
+#elif SIZEOF_VOIDP == 4
+    return ntz_int32(x);
+#endif
+}
+
 #if HAVE_LONG_LONG && SIZEOF_LONG * 2 <= SIZEOF_LONG_LONG
 # define DLONG LONG_LONG
 # define DL2NUM(x) LL2NUM(x)
-- 
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