| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Disservin
Date: Sat Jan 10 15:36:52 2026 +0100 Timestamp: 1768055812 Compiler Check Compiles and Runs Stockfish on all supported gcc & clang compilers. Only linux and avx2 currently. closes https://github.com/official-stockfish/Stockfish/pull/6533 No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Disservin
Date: Sat Jan 10 15:34:37 2026 +0100 Timestamp: 1768055677 Fix Compiler Warning Only the one on line 158 is actually required but doesn't hurt to add constexpr where applicable here. Warning was "comparison of unsigned expression in '< 0' is always false" closes https://github.com/official-stockfish/Stockfish/pull/6530 No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Disservin
Date: Sat Jan 10 15:33:36 2026 +0100 Timestamp: 1768055616 Fix Clang Tbprobe Miscompilation Recent changes to the Square enum (reducing it from int32_t to int8_t) now allow the compiler to vectorize loops that were previously too wide for targets below AVX-512. However, this vectorization which Clang performs is not correct and causes a miscompilation. Disable this vectorization. This particular issue was noticable with Clang 15 and Clang 19, on avx2 as well as applie-silicon. Ref: #6063 Original Clang Issue: llvm/llvm-project#80494 First reported by #6528, though misinterpreted. closes #6529 No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Jakub Ciolek
Date: Tue Jan 6 12:08:08 2026 +0100 Timestamp: 1767697688 qsearch: prevent bestValue from going down The bestValue can sometimes go down. This happens 2% of the time or so. This fix stops it from decreasing. Failed gainer STC: LLR: -2.94 (-2.94,2.94) <0.00,2.00> Total: 146176 W: 37930 L: 37976 D: 70270 Elo -0.11 Ptnml(0-2): 480, 17422, 37366, 17304, 516 https://tests.stockfishchess.org/tests/view/6953be19572093c1986da66a Passed Non-regression LTC: LLR: 2.95 (-2.94,2.94) <-1.75,0.25> Total: 257796 W: 65662 L: 65683 D: 126451 Elo -0.03 Ptnml(0-2): 164, 28247, 72087, 28246, 154 https://tests.stockfishchess.org/tests/view/69554ff0d844c1ce7cc7e333 closes https://github.com/official-stockfish/Stockfish/pull/6520 fixes https://github.com/official-stockfish/Stockfish/issues/6519 Bench: 2477446 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: anematode
Date: Tue Jan 6 12:02:37 2026 +0100 Timestamp: 1767697357 Network loading refactoring closes https://github.com/official-stockfish/Stockfish/pull/6523 No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Syine Mineta
Date: Tue Jan 6 12:01:01 2026 +0100 Timestamp: 1767697261 Fix remote access bug across NUMA nodes Ensure that thread-local data is created within the correct NUMA context, so that thread stacks or thread-local storage are allocated to proper NUMA nodes. refs https://github.com/official-stockfish/Stockfish/issues/6516 closes https://github.com/official-stockfish/Stockfish/pull/6518 No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Joost VandeVondele
Date: Thu Jan 1 16:17:38 2026 +0100 Timestamp: 1767280658 Update of the year Happy New Year! closes https://github.com/official-stockfish/Stockfish/pull/6514 No functional change see source |
| Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: mstembera
Date: Thu Jan 1 16:13:44 2026 +0100 Timestamp: 1767280424 Minor cleanup in full_threats.cpp closes https://github.com/official-stockfish/Stockfish/pull/6509 No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: FauziAkram
Date: Thu Jan 1 16:12:35 2026 +0100 Timestamp: 1767280355 Replacing nested loops with a single range-based for loop closes https://github.com/official-stockfish/Stockfish/pull/6503 No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: anematode
Date: Thu Jan 1 16:08:03 2026 +0100 Timestamp: 1767280083 simplify find_nnz a bit This code path is never taken for vector sizes >= 512, so we can simplify it. closes https://github.com/official-stockfish/Stockfish/pull/6501 No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: ppigazzini
Date: Thu Jan 1 16:06:25 2026 +0100 Timestamp: 1767279985 build: rename WINE_PATH to RUN_PREFIX for wrapper execution WINE_PATH started as a Wine-specific knob, but it’s now used more generally as a command prefix to run the built engine under wrappers like Intel SDE, qemu-user, etc. - Add RUN_PREFIX as the supported “run wrapper/prefix” variable in Makefile - Set WINE_PATH as a deprecated alias - Update CI and scripts to use RUN_PREFIX closes https://github.com/official-stockfish/Stockfish/pull/6500 No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: anematode
Date: Thu Jan 1 16:04:43 2026 +0100 Timestamp: 1767279883 port get_changed_pieces to ARM NEON passed STC: LLR: 2.94 (-2.94,2.94) <0.00,2.00> Total: 71968 W: 18833 L: 18489 D: 34646 Elo +1.66 Ptnml(0-2): 192, 7310, 20643, 7640, 199 https://tests.stockfishchess.org/tests/view/69509e5c572093c1986d7a0a closes https://github.com/official-stockfish/Stockfish/pull/6512 No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Michael Chaly
Date: Thu Jan 1 15:53:04 2026 +0100 Timestamp: 1767279184 Adjust main history with every new root position this patch dampens down main history to 3/4 of it value for all possible moves at the start of ID loop, making it partially refresh with every new root position. Passed STC: https://tests.stockfishchess.org/tests/view/694e33ff572093c1986d7234 LLR: 2.93 (-2.94,2.94) <0.00,2.00> Total: 115520 W: 30164 L: 29735 D: 55621 Elo +1.29 Ptnml(0-2): 395, 13192, 30192, 13551, 430 Passed LTC: https://tests.stockfishchess.org/tests/view/6950cbe6572093c1986d816c LLR: 2.95 (-2.94,2.94) <0.50,2.50> Total: 63672 W: 16480 L: 16114 D: 31078 Elo +2.00 Ptnml(0-2): 46, 6524, 18329, 6892, 45 closes https://github.com/official-stockfish/Stockfish/pull/6504 bench 2710946 see source |
| Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Steinar H. Gunderson
Date: Thu Jan 1 15:52:01 2026 +0100 Timestamp: 1767279121 Fix feature check Use _POSIX_C_SOURCE to check for PTHREAD_MUTEX_ROBUST support. The latter is a enum, not a defined variable. closes https://github.com/official-stockfish/Stockfish/pull/6510 No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Joost VandeVondele
Date: Thu Jan 1 15:51:09 2026 +0100 Timestamp: 1767279069 Fix incorrect initialization Fixes https://github.com/official-stockfish/Stockfish/issues/6505 Missing initialization seemingly resulting in side effects, as discussed in the issue. Credit to Sopel for spotting the bug. PR used as a testcase for CoPilot, doing the right thing https://github.com/official-stockfish/Stockfish/pull/6478#discussion_r2655467218 closes https://github.com/official-stockfish/Stockfish/pull/6511 No functional change see source |
| Windows x64 for modern computers + AVX2 Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Timothy Herchen
Date: Sun Dec 28 14:59:26 2025 +0100 Timestamp: 1766930366 Remove -Wstack-usage on (apple) clang Clang pretends to be GCC, but is enraged by `-Wstack-usage`: closes https://github.com/official-stockfish/Stockfish/pull/6499 No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: anematode
Date: Sun Dec 28 14:59:09 2025 +0100 Timestamp: 1766930349 Shared pawn history [Passed STC SMP](https://tests.stockfishchess.org/tests/view/694e506c572093c1986d7276): ``` LLR: 2.97 (-2.94,2.94) <0.00,2.00> Total: 14992 W: 3924 L: 3653 D: 7415 Elo +6.28 Ptnml(0-2): 20, 1547, 4090, 1820, 19 ``` [Passed LTC SMP](https://tests.stockfishchess.org/tests/live_elo/694ead61572093c1986d7365): ``` LLR: 2.94 (-2.94,2.94) <0.50,2.50> Total: 41146 W: 10654 L: 10342 D: 20150 Elo +2.63 Ptnml(0-2): 17, 3999, 12225, 4319, 13 ``` [Passed a sanity check STC SMP post-refactoring](https://tests.stockfishchess.org/tests/view/69503997572093c1986d763a): ``` LLR: 2.94 (-2.94,2.94) <0.00,2.00> Total: 46728 W: 12178 L: 11863 D: 22687 Elo +2.34 Ptnml(0-2): 82, 5093, 12685, 5436, 68 ``` (The large gain of the first STC was probably a fluke, and this result is more reasonable!) After shared correction history, Viz suggested we try sharing other histories, especially `pawnHistory`. As far as we're aware, sharing history besides correction history (like Caissa does) is novel. The implementation follows the same pattern as shared correction history – the size of the history table is scaled with `next_power_of_two(threadsInNumaNode)` and the entry is prefetched in `do_move`. A bit of refactoring was done to accommodate this new history. Note that we prefetch `&history->pawn_entry(*this)[pc][to]` rather than `&history->pawn_entry(*this)` because unlike the other entries, each entry contains multiple cache lines. closes https://github.com/official-stockfish/Stockfish/pull/6498 Bench: 2503391 Co-authored-by: Michael Chaly <> see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Stefan Geschwentner
Date: Sun Dec 28 14:55:55 2025 +0100 Timestamp: 1766930155 For expected ALL nodes scale up reduction with depth dependent factor. Passed STC: LLR: 2.93 (-2.94,2.94) <0.00,2.00> Total: 141120 W: 36860 L: 36390 D: 67870 Elo +1.16 Ptnml(0-2): 470, 16441, 36314, 16819, 516 https://tests.stockfishchess.org/tests/view/694978e93c8768ca45072763 Passed LTC: LLR: 2.94 (-2.94,2.94) <0.50,2.50> Total: 66576 W: 17078 L: 16700 D: 32798 Elo +1.97 Ptnml(0-2): 45, 7093, 18628, 7483, 39 https://tests.stockfishchess.org/tests/view/694bb608572093c1986d6ba6 closes https://github.com/official-stockfish/Stockfish/pull/6496 Bench: 2503391 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: KazApps
Date: Sun Dec 28 14:55:47 2025 +0100 Timestamp: 1766930147 Fix nonPawnKey Fix incorrect nonPawnKey update Passed non-reg SMP STC: ``` LLR: 2.93 (-2.94,2.94) <-1.75,0.25> Total: 139424 W: 35792 L: 35690 D: 67942 Elo +0.25 Ptnml(0-2): 197, 15783, 37665, 15855, 212 ``` https://tests.stockfishchess.org/tests/view/694b7b7e572093c1986d6b0d Passed non-reg SMP LTC: ``` LLR: 2.95 (-2.94,2.94) <-1.75,0.25> Total: 88880 W: 22863 L: 22718 D: 43299 Elo +0.57 Ptnml(0-2): 16, 8947, 26401, 9028, 48 ``` https://tests.stockfishchess.org/tests/view/694d2ceb572093c1986d6fc8 fixes https://github.com/official-stockfish/Stockfish/issues/6492 closes https://github.com/official-stockfish/Stockfish/pull/6494 Bench: 2475788 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Daniel Monroe
Date: Sun Dec 28 14:53:12 2025 +0100 Timestamp: 1766929992 Simplify doDeeperSearch Passed simplification STC LLR: 2.93 (-2.94,2.94) <-1.75,0.25> Total: 92096 W: 23888 L: 23728 D: 44480 Elo +0.60 Ptnml(0-2): 336, 10796, 23608, 10988, 320 https://tests.stockfishchess.org/tests/view/694b6b9d572093c1986d6ae0 Passed simplification LTC LLR: 2.96 (-2.94,2.94) <-1.75,0.25> Total: 50064 W: 12789 L: 12598 D: 24677 Elo +1.33 Ptnml(0-2): 24, 5350, 14103, 5521, 34 https://tests.stockfishchess.org/tests/view/694d49aa572093c1986d7021 closes https://github.com/official-stockfish/Stockfish/pull/6493 Bench: 2494221 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Joost VandeVondele
Date: Sun Dec 28 14:51:56 2025 +0100 Timestamp: 1766929916 Update Top CPU Contributors update to current closes https://github.com/official-stockfish/Stockfish/pull/6491 No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: FauziAkram
Date: Sun Dec 28 14:50:36 2025 +0100 Timestamp: 1766929836 Removing redundant parentheses closes https://github.com/official-stockfish/Stockfish/pull/6490 No functional change see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: FauziAkram
Date: Sun Dec 28 14:49:19 2025 +0100 Timestamp: 1766929759 Refine reduction logic based on next-ply cutoff count Passed STC: LLR: 2.95 (-2.94,2.94) <0.00,2.00> Total: 38208 W: 10076 L: 9754 D: 18378 Elo +2.93 Ptnml(0-2): 139, 4390, 9742, 4676, 157 https://tests.stockfishchess.org/tests/view/6945bb6446f342e1ec211d93 Passed LTC: LLR: 2.95 (-2.94,2.94) <0.50,2.50> Total: 64086 W: 16529 L: 16157 D: 31400 Elo +2.02 Ptnml(0-2): 34, 6808, 17990, 7174, 37 https://tests.stockfishchess.org/tests/view/69479d303c8768ca45072446 closes https://github.com/official-stockfish/Stockfish/pull/6489 Bench: 2442415 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Taras Vuk
Date: Tue Dec 23 21:42:45 2025 +0100 Timestamp: 1766522565 Incorporate statscore into history bonus Passed STC: LLR: 2.94 (-2.94,2.94) <0.00,2.00> Total: 80128 W: 20879 L: 20498 D: 38751 Elo +1.65 Ptnml(0-2): 274, 9318, 20496, 9705, 271 https://tests.stockfishchess.org/tests/view/6945d11f3c8768ca45072218 Passed LTC: LLR: 2.94 (-2.94,2.94) <0.50,2.50> Total: 134298 W: 34497 L: 33983 D: 65818 Elo +1.33 Ptnml(0-2): 81, 14334, 37812, 14834, 88 https://tests.stockfishchess.org/tests/view/6947bf033c8768ca45072491 closes https://github.com/official-stockfish/Stockfish/pull/6488 Bench: 2325401 see source |
| Windows x64 for Haswell CPUs Windows x64 for modern computers + AVX2 Windows x64 for modern computers Windows x64 + SSSE3 Windows x64 Linux x64 for Haswell CPUs Linux x64 for modern computers + AVX2 Linux x64 for modern computers Linux x64 + SSSE3 Linux x64 | Author: Disservin
Date: Tue Dec 23 21:42:45 2025 +0100 Timestamp: 1766522565 Init threat offsets at compile time Init threat offsets at compile time. Avoid another global init function call. Passed STC Non-Regression: https://tests.stockfishchess.org/tests/view/694971a83c8768ca4507275c LLR: 2.94 (-2.94,2.94) <-1.75,0.25> Total: 43296 W: 11284 L: 11077 D: 20935 Elo +1.66 Ptnml(0-2): 152, 4611, 11924, 4800, 161 closes https://github.com/official-stockfish/Stockfish/pull/6487 No functional change see source |