Commit to 32-bit versions

CMakeLists.txt

@@ -59,10 +59,6 @@ cmake_pop_check_state()
 
 option(USE_SIMD_FALLBACK
        "Use fallback implementations of functions that use SIMD" OFF)
-option(
-  USE_32_BIT_VERSIONS
-  "Store 32 bit versions internally, and rely on versions never being different by more than 2e9"
-  OFF)
 
 # This is encouraged according to
 # https://valgrind.org/docs/manual/manual-core-adv.html#manual-core-adv.clientreq
@@ -107,10 +103,6 @@ if(NOT USE_SIMD_FALLBACK)
   endif()
 endif()
 
-if(USE_32_BIT_VERSIONS)
-  add_compile_definitions(INTERNAL_VERSION_32_BIT=1)
-endif()
-
 set(CMAKE_CXX_IMPLICIT_LINK_LIBRARIES "")
 
 add_library(${PROJECT_NAME}-object OBJECT ConflictSet.cpp)

ConflictSet.cpp

@@ -78,11 +78,6 @@ constexpr void removeKey(struct Node *) {}
 
 // ==================== BEGIN IMPLEMENTATION ====================
 
-#ifndef INTERNAL_VERSION_32_BIT
-#define INTERNAL_VERSION_32_BIT 0
-#endif
-
-#if INTERNAL_VERSION_32_BIT
 struct InternalVersionT {
   constexpr InternalVersionT() = default;
   constexpr explicit InternalVersionT(int64_t value) : value(value) {}
@@ -99,20 +94,6 @@ private:
   uint32_t value;
 };
 thread_local InternalVersionT InternalVersionT::zero;
-#else
-struct InternalVersionT {
-  constexpr InternalVersionT() = default;
-  constexpr explicit InternalVersionT(int64_t value) : value(value) {}
-  constexpr int64_t toInt64() const { return value; } // GCOVR_EXCL_LINE
-  constexpr auto operator<=>(const InternalVersionT &rhs) const = default;
-  constexpr bool operator==(const InternalVersionT &) const = default;
-  static const InternalVersionT zero;
-
-private:
-  int64_t value;
-};
-const InternalVersionT InternalVersionT::zero{0};
-#endif
 
 struct Entry {
   InternalVersionT pointVersion;
@@ -527,13 +508,8 @@ std::string getSearchPath(Node *n);
 // Each node with an entry present gets a budget of kBytesPerKey. Node0 always
 // has an entry present.
 // Induction hypothesis is that each node's surplus is >= kMinNodeSurplus
-#if INTERNAL_VERSION_32_BIT
 constexpr int kBytesPerKey = 112;
 constexpr int kMinNodeSurplus = 80;
-#else
-constexpr int kBytesPerKey = 144;
-constexpr int kMinNodeSurplus = 104;
-#endif
 constexpr int kMinChildrenNode3 = 2;
 constexpr int kMinChildrenNode16 = 4;
 constexpr int kMinChildrenNode48 = 17;
@@ -1833,7 +1809,6 @@ bool scan16(const InternalVersionT *vs, const uint8_t *is, int begin, int end,
   uint64_t mask = vget_lane_u64(
       vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(results), 4)), 0);
 
-#if INTERNAL_VERSION_32_BIT
   uint32x4_t w4[4];
   memcpy(w4, vs, sizeof(w4));
   uint32_t rv;
@@ -1853,12 +1828,6 @@ bool scan16(const InternalVersionT *vs, const uint8_t *is, int begin, int end,
 
   uint64_t compared = vget_lane_u64(
       vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(combined), 4)), 0);
-#else
-  uint64_t compared = 0;
-  for (int i = 0; i < 16; ++i) {
-    compared |= uint64_t(vs[i] > readVersion) << (i << 2);
-  }
-#endif
 
   return !(compared & mask);
 
@@ -1871,17 +1840,11 @@ bool scan16(const InternalVersionT *vs, const uint8_t *is, int begin, int end,
       indices, _mm_max_epu8(indices, _mm_set1_epi8(end - begin))));
 
   uint32_t compared = 0;
-#if INTERNAL_VERSION_32_BIT
   if constexpr (kAVX512) {
     compared = compare16_32bit_avx512(vs, readVersion);
   } else {
     compared = compare16_32bit(vs, readVersion);
   }
-#else
-  for (int i = 0; i < 16; ++i) {
-    compared |= (vs[i] > readVersion) << i;
-  }
-#endif
   return !(compared & mask);
 
 #else
@@ -1914,7 +1877,7 @@ scan16(const InternalVersionT *vs, int begin, int end,
   assert(0 <= end && end <= 16);
   assert(begin <= end);
 
-#if INTERNAL_VERSION_32_BIT && defined(HAS_ARM_NEON)
+#if defined(HAS_ARM_NEON)
   uint32x4_t w4[4];
   memcpy(w4, vs, sizeof(w4));
   uint32_t rv;
@@ -1938,7 +1901,7 @@ scan16(const InternalVersionT *vs, int begin, int end,
   conflict &= end == 16 ? -1 : (uint64_t(1) << (end << 2)) - 1;
   conflict >>= begin << 2;
   return !conflict;
-#elif INTERNAL_VERSION_32_BIT && defined(HAS_AVX)
+#elif defined(HAS_AVX)
   uint32_t conflict;
   if constexpr (kAVX512) {
     conflict = compare16_32bit_avx512(vs, readVersion);
@@ -2886,9 +2849,7 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
   void addWrites(const WriteRange *writes, int count, int64_t writeVersion) {
     assert(writeVersion >= newestVersionFullPrecision);
     newestVersionFullPrecision = writeVersion;
-#if INTERNAL_VERSION_32_BIT
     InternalVersionT::zero = oldestVersion;
-#endif
     for (int i = 0; i < count; ++i) {
       const auto &w = writes[i];
       auto begin = std::span<const uint8_t>(w.begin.p, w.begin.len);
@@ -2910,9 +2871,7 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
     assert(o >= oldestVersionFullPrecision);
     this->oldestVersionFullPrecision = o;
     this->oldestVersion = oldestVersion;
-#if INTERNAL_VERSION_32_BIT
     InternalVersionT::zero = oldestVersion;
-#endif
 #ifdef NDEBUG
     // This is here for performance reasons, since we want to amortize the cost
     // of storing the search path as a string. In tests, we want to exercise the