Use simde so SIMD speedups work on ARM as well

bypy/sources.json

@@ -250,6 +250,15 @@
         }
     },
 
+    {
+        "name": "simde",
+        "unix": {
+            "filename": "simde-amalgamated-0.7.6.tar.xz",
+            "hash": "sha256:703eac1f2af7de1f7e4aea2286130b98e1addcc0559426e78304c92e2b4eb5e1",
+            "urls": ["https://github.com/simd-everywhere/simde/releases/download/v0.7.6/{filename}"]
+        }
+    },
+
     {
         "name": "wayland",
         "os": "linux",

docs/build.rst

@@ -96,6 +96,7 @@ Run-time dependencies:
 Build-time dependencies:
 
 * ``gcc`` or ``clang``
+* ``simde``
 * ``go`` >= _build_go_version (see :file:`go.mod` for go packages used during building)
 * ``pkg-config``
 * For building on Linux in addition to the above dependencies you might also

kitty/simd-string.c

@@ -5,9 +5,10 @@
  * Distributed under terms of the GPL3 license.
  */
 
+#define SIMDE_ENABLE_NATIVE_ALIASES
 #include "data-types.h"
 #include "simd-string.h"
-#include <immintrin.h>
+#include <simde/x86/avx2.h>
 
 static bool has_sse4_2 = false, has_avx2 = false;
 
@@ -194,7 +195,18 @@ bool
 init_simd(void *x) {
     PyObject *module = (PyObject*)x;
 #define A(x, val) { Py_INCREF(Py_##val); if (0 != PyModule_AddObject(module, #x, Py_##val)) return false; }
+#ifdef __APPLE__
+    // Modern Apple Intel processors should all support AVX2. And simde takes care of NEON on Apple Silicon
+    has_sse4_2 = true; has_avx2 = true;
+#else
+#ifdef __aarch64__
+    // no idea how to probe ARM cpu for NEON support. This file uses pretty
+    // basic AVX2 and SSE4.2 intrinsics, so hopefully they work on ARM
+    has_sse4_2 = true; has_avx2 = true;
+#else
     has_sse4_2 = __builtin_cpu_supports("sse4.2") != 0; has_avx2 = __builtin_cpu_supports("avx2");
+#endif
+#endif
     if (has_avx2) {
         A(has_avx2, True);
         find_byte_not_in_range_impl = find_byte_not_in_range_avx2;