diff --git a/Makefile b/Makefile
index 3dc2ea1..fb5ba98 100644
--- a/Makefile
+++ b/Makefile
@@ -67,7 +67,7 @@ endif
 EVALFILE = weights/master.bin
 TMP_EVALFILE = tmp.bin
 DEFINE_FLAGS += -DVERSION=\"v$(VERSION_MAJOR).$(VERSION_MINOR).$(HASH)\" -DNDEBUG -D_CRT_SECURE_NO_WARNINGS
-CXXFLAGS = $(DEFINE_FLAGS) $(ARCH_FLAGS) -std=c++20 -O3 -flto -pthread -Wall
+CXXFLAGS = $(DEFINE_FLAGS) $(ARCH_FLAGS) -std=c++20 -O3 -flto=auto -pthread -Wall
 EXE = $(NAME)
 OUTPUT_BINARY = $(EXE)$(SUFFIX)
 INCBIN_TOOL = incbin_tool$(SUFFIX)
diff --git a/src/chess/bitboard.h b/src/chess/bitboard.h
index 7496cf2..a818ccf 100644
--- a/src/chess/bitboard.h
+++ b/src/chess/bitboard.h
@@ -33,9 +33,9 @@ namespace chess {
     // Used for referencing the 64 squares of a board using a 64-bit number
     struct Bitboard {
 
-        U64 bb = 0;
+        uint64_t bb = 0;
 
-        constexpr Bitboard(U64 value) {
+        constexpr Bitboard(uint64_t value) {
             bb = value;
         }
 
@@ -143,7 +143,7 @@ namespace chess {
             return bb;
         }
 
-        [[nodiscard]] constexpr explicit operator U64() const {
+        [[nodiscard]] constexpr explicit operator uint64_t() const {
             return bb;
         }
     };
diff --git a/src/chess/constants.h b/src/chess/constants.h
index abaa2d2..1049195 100644
--- a/src/chess/constants.h
+++ b/src/chess/constants.h
@@ -32,7 +32,6 @@
 #define AVX2
 #endif
 
-using U64 = uint64_t;
 using Score = int32_t;
 using Depth = int8_t;
 using Ply = int8_t;
diff --git a/src/chess/magic.h b/src/chess/magic.h
index dd47c31..21f6a85 100644
--- a/src/chess/magic.h
+++ b/src/chess/magic.h
@@ -75,7 +75,7 @@ namespace chess {
             } while (occ != 0);
 
             for (size_t i = 0; i < length; i++) {
-                U64 index = get_magic_index(magic, occupied[i]);
+                uint64_t index = get_magic_index(magic, occupied[i]);
 
                 magic.ptr[index] = attacked[i];
             }
diff --git a/src/chess/randoms.h b/src/chess/randoms.h
index 8976fad..e1bb16d 100644
--- a/src/chess/randoms.h
+++ b/src/chess/randoms.h
@@ -20,18 +20,18 @@
 #include "constants.h"
 
 namespace chess {
-    extern const U64 rand_table[793];
+    extern const uint64_t rand_table[793];
 
-    constexpr U64 const *rand_table_pieces = rand_table;
-    constexpr U64 const *rand_table_castling = rand_table + 768;
-    constexpr U64 const *rand_table_ep = rand_table + 784;
-    constexpr U64 const *rand_table_color = rand_table + 792;
+    constexpr uint64_t const *rand_table_pieces = rand_table;
+    constexpr uint64_t const *rand_table_castling = rand_table + 768;
+    constexpr uint64_t const *rand_table_ep = rand_table + 784;
+    constexpr uint64_t const *rand_table_color = rand_table + 792;
 
     // 2 colors * 6 types * 64 square = 768
     // 16 for castling rights
     // 8 number for the file of the epSquare
     // 1 number if the side is black
-    constexpr U64 rand_table[793] = {
+    constexpr uint64_t rand_table[793] = {
             0x4ef488bfae17abbaULL, 0x1b608e38d5cf7308ULL,
             0x851dabc8d9c029daULL, 0x62ff3fd5ca1fe189ULL,
             0xb58f435e51ec54d9ULL, 0xd6478aa5957c39eaULL,
diff --git a/src/chess/zobrist.h b/src/chess/zobrist.h
index 33bf3d5..2f5c2e6 100644
--- a/src/chess/zobrist.h
+++ b/src/chess/zobrist.h
@@ -24,13 +24,13 @@
 namespace chess {
     struct Zobrist {
 
-        U64 hash = 0;
+        uint64_t hash = 0;
 
         Zobrist() = default;
 
-        explicit Zobrist(U64 hash) : hash(hash) {}
+        explicit Zobrist(uint64_t hash) : hash(hash) {}
 
-        [[nodiscard]] operator U64() const {
+        [[nodiscard]] operator uint64_t() const {
             return hash;
         }
 
diff --git a/src/network/layers/accumulator.h b/src/network/layers/accumulator.h
index b797b00..4558e0a 100644
--- a/src/network/layers/accumulator.h
+++ b/src/network/layers/accumulator.h
@@ -96,7 +96,10 @@ namespace nn::layers {
         void push(std::array<T, OUT> &result) {
 
 #ifdef AVX2
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wignored-attributes"
             static_assert(std::is_invocable_r_v<__m256i, decltype(ACTIVATION::_mm256_forward_epi16), __m256i>, "ACTIVATION::forward doesn't support AVX2 registers");
+#pragma GCC diagnostic pop
 
             for (size_t i = 0; i < chunk_count; i++) {
                 const size_t offset = i * register_width;
diff --git a/src/network/train.h b/src/network/train.h
index a688a93..e65ae7b 100644
--- a/src/network/train.h
+++ b/src/network/train.h
@@ -83,7 +83,7 @@ namespace nn {
                     std::thread th_loading = std::thread(&DataParser::read_batch, &training_parser, batch_size, entries_next, std::ref(is_new_epoch));
 
                     std::vector<std::thread> ths;
-                    for (int id = 0; id < thread_count; id++) {
+                    for (size_t id = 0; id < thread_count; id++) {
                         ths.emplace_back(&Trainer::process_batch<true>, this, id);
                     }
 
@@ -93,7 +93,7 @@ namespace nn {
 
                     adam.update(gradients, network);
 
-                    for (int id = 0; id < thread_count; id++) {
+                    for (size_t id = 0; id < thread_count; id++) {
                         checkpoint_error += errors[id];
                         checkpoint_accuracy += accuracy[id];
                     }
@@ -177,7 +177,7 @@ namespace nn {
             float val_loss = 0.0f;
             int correct = 0.0f;
 
-            for (int id = 0; id < thread_count; id++) {
+            for (size_t id = 0; id < thread_count; id++) {
                 val_loss += errors[id];
                 correct += accuracy[id];
             }
diff --git a/src/search/transposition_table.h b/src/search/transposition_table.h
index 3f125e3..2974287 100644
--- a/src/search/transposition_table.h
+++ b/src/search/transposition_table.h
@@ -34,23 +34,35 @@ namespace search {
         TT_BETA = 3
     };
 
-    struct TTEntry {           // Total: 16 bytes
-        U64 hash;              // 8 bytes
-        Score eval;            // 4 bytes
-        chess::Move hash_move; // 2 bytes
-        Depth depth;           // 1 byte
-        TTFlag flag;           // 1 byte
+    struct TTEntry {                              // Total: 16 bytes
+        uint64_t hash = 0;                        // 8 bytes
+        Score eval = 0;                           // 4 bytes
+        chess::Move hash_move = chess::NULL_MOVE; // 2 bytes
+        Depth depth = 0;                          // 1 byte
+        TTFlag flag = TT_NONE;                    // 1 byte
+
+        constexpr TTEntry() = default;
     };
 
     static_assert(sizeof(TTEntry) == 16);
 
     class TT {
     public:
-        void resize(unsigned int MB) {
-            if (bucket_count)
+        ~TT() {
+            free_table();
+        }
+
+        void free_table() {
+            if (bucket_count) {
                 free(table);
+                bucket_count = 0;
+            }
+        }
 
-            unsigned int i = 10;
+        void resize(unsigned int MB) {
+            free_table();
+
+            uint64_t i = 10;
             while ((1ULL << i) <= MB * 1024ULL * 1024ULL / sizeof(TTEntry))
                 i++;
 
@@ -58,15 +70,15 @@ namespace search {
             mask = bucket_count - 1ULL;
 
             table = (TTEntry *) malloc(bucket_count * sizeof(TTEntry));
-
-            clear();
         }
 
         void clear() {
-            std::memset(table, 0, bucket_count * sizeof(TTEntry));
+            for (uint64_t i = 0; i < bucket_count; i++) {
+                table[i] = TTEntry();
+            }
         }
 
-        std::optional<TTEntry> probe(U64 hash) {
+        std::optional<TTEntry> probe(uint64_t hash) {
             TTEntry entry = *get_entry(hash);
 
             if (entry.hash != hash)
@@ -75,7 +87,7 @@ namespace search {
             return entry;
         }
 
-        void save(U64 hash, Depth depth, Score eval, TTFlag flag, chess::Move best_move) {
+        void save(uint64_t hash, Depth depth, Score eval, TTFlag flag, chess::Move best_move) {
             TTEntry *entry = get_entry(hash);
 
             if (flag == TT_ALPHA && entry->hash == hash) {
@@ -94,11 +106,11 @@ namespace search {
             }
         }
 
-        void prefetch(U64 hash) {
+        void prefetch(uint64_t hash) {
             __builtin_prefetch(get_entry(hash), 0);
         }
 
-        chess::Move get_hash_move(U64 hash) {
+        chess::Move get_hash_move(uint64_t hash) {
             TTEntry *entry = get_entry(hash);
             if (entry->hash == hash)
                 return entry->hash_move;
@@ -106,11 +118,11 @@ namespace search {
         }
 
     private:
-        TTEntry *table;
-        unsigned int bucket_count = 0;
-        U64 mask = 0;
+        TTEntry *table = nullptr;
+        uint64_t bucket_count = 0;
+        uint64_t mask = 0;
 
-        TTEntry *get_entry(U64 hash) {
+        TTEntry *get_entry(uint64_t hash) {
             return table + (hash & mask);
         }
     };
diff --git a/src/selfplay/engine.h b/src/selfplay/engine.h
index 004f3fe..0f5f88a 100644
--- a/src/selfplay/engine.h
+++ b/src/selfplay/engine.h
@@ -30,6 +30,7 @@ namespace selfplay {
         void init(unsigned int hash_size, unsigned int thread_count) {
             sm.allocate_hash(hash_size);
             sm.allocate_threads(thread_count);
+            sm.tt_clear();
         }
 
         std::pair<chess::Move, Score> search(const chess::Board &board, const search::Limits &limits) {
diff --git a/src/tests/hash.h b/src/tests/hash.h
index 9bf65fa..a2016fb 100644
--- a/src/tests/hash.h
+++ b/src/tests/hash.h
@@ -32,7 +32,7 @@ namespace test {
             std::vector<std::string> moves;
             chess::Zobrist hash;
 
-            Test(std::string fen, std::vector<std::string> moves, U64 hash) : fen(std::move(fen)), moves(std::move(moves)), hash(hash) {}
+            Test(std::string fen, std::vector<std::string> moves, uint64_t hash) : fen(std::move(fen)), moves(std::move(moves)), hash(hash) {}
         };
 
         const std::vector<Test> tests = {
diff --git a/src/uci/uci.h b/src/uci/uci.h
index 8b30870..1fd61e4 100644
--- a/src/uci/uci.h
+++ b/src/uci/uci.h
@@ -131,7 +131,7 @@ namespace uci {
         });
         commands.emplace_back("perft", [&](context tokens) {
             int depth = find_element<int>(tokens, "perft").value_or(5);
-            U64 node_count = test::perft<true, false>(board, depth);
+            uint64_t node_count = test::perft<true, false>(board, depth);
             Logger("Total node count: ", node_count);
         });
         commands.emplace_back("go", [&](context tokens) {