optimized SSE2-based group15

include/boost/unordered/detail/foa.hpp

@@ -135,6 +135,7 @@ static const std::size_t default_bucket_count = 0;
 
 #if defined(BOOST_UNORDERED_SSE2)
 
+#if 0
 struct group15
 {
   static constexpr int N=15;
@@ -299,6 +300,157 @@ private:
 
   alignas(16) __m128i m;
 };
+#else
+struct group15
+{
+  static constexpr int N=15;
+
+  struct dummy_group_type
+  {
+    alignas(16) unsigned char storage[N+1]={0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0};
+  };
+
+  inline void initialize(){m=_mm_setzero_si128();}
+
+  inline void set(std::size_t pos,std::size_t hash)
+  {
+    BOOST_ASSERT(pos<N);
+    at(pos)=reduced_hash(hash+pos);
+  }
+
+  inline void set_sentinel()
+  {
+    at(N-1)=sentinel_;
+  }
+
+  inline bool is_sentinel(std::size_t pos)const
+  {
+    BOOST_ASSERT(pos<N);
+    return at(pos)==sentinel_;
+  }
+
+  inline void reset(std::size_t pos)
+  {
+    BOOST_ASSERT(pos<N);
+    at(pos)=available_;
+  }
+
+  static inline void reset(unsigned char* pc)
+  {
+    *pc=available_;
+  }
+
+  inline int match(std::size_t hash)const
+  {
+    return _mm_movemask_epi8(_mm_cmpeq_epi8(m,match_word(hash)))&0x7FFF;
+  }
+
+  inline bool is_not_overflowed(std::size_t hash)const
+  {
+    static constexpr unsigned char shift[]={1,2,4,8,16,32,64,128};
+
+    return !(overflow()&shift[hash%8]);
+  }
+
+  inline void mark_overflow(std::size_t hash)
+  {
+#if BOOST_WORKAROUND(BOOST_GCC, >= 50000 && BOOST_GCC < 60000)
+    overflow() = static_cast<unsigned char>( overflow() | static_cast<unsigned char>(1<<(hash%8)) );
+#else
+    overflow()|=static_cast<unsigned char>(1<<(hash%8));
+#endif
+  }
+
+  static inline bool maybe_caused_overflow(unsigned char* pc)
+  {
+    std::size_t pos=reinterpret_cast<uintptr_t>(pc)%sizeof(group15);
+    group15    *pg=reinterpret_cast<group15*>(pc-pos);
+    return !pg->is_not_overflowed(*pc-pos);
+  };
+
+  inline int match_available()const
+  {
+    return _mm_movemask_epi8(
+      _mm_cmpeq_epi8(m,_mm_setzero_si128()))&0x7FFF;
+  }
+
+  inline int match_occupied()const
+  {
+    return (~match_available())&0x7FFF;
+  }
+
+  inline int match_really_occupied()const /* excluding sentinel */
+  {
+    return at(N-1)==sentinel_?match_occupied()&0x3FFF:match_occupied();
+  }
+
+private:
+  static constexpr unsigned char available_=0,
+                                 sentinel_=1;
+
+  static constexpr unsigned char reduced_hash_table[]={
+    8,9,2,3,4,5,6,7,8,9,10,11,12,13,14,15,
+    16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,
+    32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,
+    48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,
+    64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,
+    80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,
+    96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,
+    112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,
+    128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,
+    144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,
+    160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,
+    176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,
+    192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,
+    208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,
+    224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,
+    240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255,
+    8,9,2,3,4,5,6,7,8,9,10,11,12,13,14,
+  };
+
+  inline static __m128i match_word(std::size_t hash)
+  {
+#if defined(__MSVC_RUNTIME_CHECKS)
+    return _mm_loadu_si128(reinterpret_cast<const __m128i*>(
+      reduced_hash_table+(hash&0xffu)));
+#else
+    return _mm_loadu_si128(reinterpret_cast<const __m128i*>(
+      reduced_hash_table+(unsigned char)(hash)));
+#endif
+  }
+
+  inline static unsigned char reduced_hash(std::size_t hash)
+  {
+#if defined(__MSVC_RUNTIME_CHECKS)
+    return reduced_hash_table[hash&0xffu];
+#else
+    return reduced_hash_table[(unsigned char)hash];
+#endif
+  }
+
+  inline unsigned char& at(std::size_t pos)
+  {
+    return reinterpret_cast<unsigned char*>(&m)[pos];
+  }
+
+  inline unsigned char at(std::size_t pos)const
+  {
+    return reinterpret_cast<const unsigned char*>(&m)[pos];
+  }
+
+  inline unsigned char& overflow()
+  {
+    return at(N);
+  }
+
+  inline unsigned char overflow()const
+  {
+    return at(N);
+  }
+
+  alignas(16) __m128i m;
+};
+#endif
 
 #elif defined(BOOST_UNORDERED_LITTLE_ENDIAN_NEON)