1 files changed, 24 insertions, 0 deletions
diff --git a/ext/json/simd/conf.rb b/ext/json/simd/conf.rb
new file mode 100644
index 0000000000..76f774bc97
--- /dev/null
+++ b/ext/json/simd/conf.rb
@@ -0,0 +1,24 @@
+case RbConfig::CONFIG['host_cpu']
+when /^(arm|aarch64)/
+  # Try to compile a small program using NEON instructions
+  header, type, init, extra = 'arm_neon.h', 'uint8x16_t', 'vdupq_n_u8(32)', nil
+when /^(x86_64|x64)/
+  header, type, init, extra = 'x86intrin.h', '__m128i', '_mm_set1_epi8(32)', 'if (__builtin_cpu_supports("sse2")) { printf("OK"); }'
+end
+if header
+  if have_header(header) && try_compile(<<~SRC, '-Werror=implicit-function-declaration')
+      #{cpp_include(header)}
+      int main(int argc, char **argv) {
+        #{type} test = #{init};
+        #{extra}
+        if (argc > 100000) printf("%p", &test);
+        return 0;
+      }
+    SRC
+    $defs.push("-DJSON_ENABLE_SIMD")
+  else
+    puts "Disable SIMD"
+  end
+end
+
+have_header('cpuid.h')