numpy · mattip · Dec 2, 2020 · Nov 7, 2020 · Nov 7, 2020 · Nov 8, 2020
diff --git a/.gitattributes b/.gitattributes
@@ -14,6 +14,7 @@ doc/release/*.rst merge=union
 numpy/linalg/lapack_lite/f2c.c linguist-vendored
 numpy/linalg/lapack_lite/f2c.h linguist-vendored
 tools/npy_tempita/* linguist-vendored
+numpy/core/include/numpy/libdivide/* linguist-vendored
 
 # Mark some files as generated
 numpy/linalg/lapack_lite/f2c_*.c linguist-generated

diff --git a/LICENSES_bundled.txt b/LICENSES_bundled.txt
@@ -15,3 +15,8 @@ Name: dragon4
 Files: numpy/core/src/multiarray/dragon4.c
 License: MIT
   For license text, see numpy/core/src/multiarray/dragon4.c
+
+Name: libdivide
+Files: numpy/core/include/numpy/libdivide/*
+License: Zlib
+  For license text, see numpy/core/include/numpy/libdivide/LICENSE.txt
diff --git a/benchmarks/benchmarks/bench_ufunc.py b/benchmarks/benchmarks/bench_ufunc.py
@@ -134,6 +134,22 @@ def time_less_than_scalar2(self, dtype):
         (self.d < 1)
 
 
+class CustomScalarFloorDivideInt(Benchmark):
+    params = ([np.int8, np.int16, np.int32, np.int64], [8, -8, 43, -43, 0])
+    param_names = ['dtype', 'divisors']
+    max_value = 10**7
+    min_value = -10**7
+
+    def setup(self, dtype, divisor):
+        iinfo = np.iinfo(dtype)
+        self.x = np.arange(
+                max(iinfo.min, self.min_value),
+                min(iinfo.max, self.max_value), dtype=dtype)
+
+    def time_floor_divide_int(self, dtpye, divisor):
+        self.x // divisor
+
+
 class Scalar(Benchmark):
     def setup(self):
         self.x = np.asarray(1.0)

diff --git a/doc/release/upcoming_changes/17727.performance.rst b/doc/release/upcoming_changes/17727.performance.rst
@@ -0,0 +1,7 @@
+Improved performance in integer division of NumPy arrays
+--------------------------------------------------------
+Integer division of NumPy arrays now uses `libdivide <https://libdivide.com/>` 
+when the divisor is a constant. With the usage of libdivde and
+other minor optimizations, there is a large speedup.
+The ``//`` operator and ``np.floor_divide`` makes use
+of the new changes.
diff --git a/numpy/core/include/numpy/libdivide/LICENSE.txt b/numpy/core/include/numpy/libdivide/LICENSE.txt
@@ -0,0 +1,21 @@
+  zlib License
+  ------------
+
+  Copyright (C) 2010 - 2019 ridiculous_fish, <libdivide@ridiculousfish.com>
+  Copyright (C) 2016 - 2019 Kim Walisch, <kim.walisch@gmail.com>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.