From 201688e0e5297592281379a55568b16a13c0b8f0 Mon Sep 17 00:00:00 2001
From: Kenjiro Nakayama <nakayamakenjiro@gmail.com>
Date: Sat, 8 Aug 2026 09:34:10 +0900
Subject: ci: run Windows ARM64 tests on native runners

Currently, ARM64 builds are cross-compiled on x64 Windows runners and
the tests are skipped.

With this change, static and shared ARM64 builds run on windows-11-arm
runners, allowing the test suite to execute natively.

Running the tests natively also exposes incorrect code generation by
the MSVC ARM64 optimizer when the generic bn_ct_ne_zero() helper is
inlined. Work around this by using the _CountLeadingZeros64() intrinsic
on MSVC ARM64, avoiding the affected optimizer transformation and
allowing the tests to pass.
---
 .github/workflows/windows.yml       | 26 ++++++++++++++++++++++----
 patches/win32_arm64_bn_arch.h.patch | 21 +++++++++++++++++++++
 2 files changed, 43 insertions(+), 4 deletions(-)
 create mode 100644 patches/win32_arm64_bn_arch.h.patch

diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index 4814ffa..27e6633 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -22,8 +22,15 @@ jobs:
       fail-fast: false
       matrix:
         os: ["windows-2022", "windows-2025"]
-        arch: ["ARM64", "x64", "Win32"]
+        arch: ["x64", "Win32"]
         shared: ["ON", "OFF"]
+        include:
+          - os: "windows-11-arm"
+            arch: "ARM64"
+            shared: "ON"
+          - os: "windows-11-arm"
+            arch: "ARM64"
+            shared: "OFF"
     steps:
       - name: "Checkout repository"
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
@@ -53,12 +60,24 @@ jobs:
           if ($LASTEXITCODE -ne 0) {
             throw "IO::Socket::SSL::Utils is unavailable"
           }
+
+          $vswhere = Join-Path ${env:ProgramFiles(x86)} 'Microsoft Visual Studio\Installer\vswhere.exe'
+          $component = if ('${{ matrix.arch }}' -eq 'ARM64') {
+            'Microsoft.VisualStudio.Component.VC.Tools.ARM64'
+          } else {
+            'Microsoft.VisualStudio.Component.VC.Tools.x86.x64'
+          }
+          $version = & $vswhere -latest -products * -requires $component -property installationVersion
+          if (-not $version) {
+            throw "No Visual Studio installation with $component found"
+          }
+          $major = $version.Split('.')[0]
           $generator = cmake --help |
-            Select-String '^\s*\*?\s*(Visual Studio \d+ \d+)' |
+            Select-String "^\s*\*?\s*(Visual Studio $major \d+)" |
             Select-Object -First 1 |
             ForEach-Object { $_.Matches[0].Groups[1].Value }
           if (-not $generator) {
-            throw "No Visual Studio CMake generator found"
+            throw "No CMake generator found for Visual Studio $major"
           }
           Write-Host "Using generator: $generator"
           cmake -Bbuild -G "$generator" -A ${{ matrix.arch }} -D BUILD_SHARED_LIBS=${{ matrix.shared }} -D CMAKE_INSTALL_PREFIX=../local "-DPERL_EXECUTABLE=$perl"
@@ -68,7 +87,6 @@ jobs:
         run: cmake --build build --config Release
 
       - name: "Test"
-        if: matrix.arch != 'ARM64'
         shell: cmd
         run: ctest --test-dir build -C Release --output-on-failure
 
diff --git a/patches/win32_arm64_bn_arch.h.patch b/patches/win32_arm64_bn_arch.h.patch
new file mode 100644
index 0000000..427ed94
--- /dev/null
+++ b/patches/win32_arm64_bn_arch.h.patch
@@ -0,0 +1,21 @@
+--- crypto/bn/arch/aarch64/bn_arch.h.orig
++++ crypto/bn/arch/aarch64/bn_arch.h
+@@ -20,4 +20,17 @@
+ #ifndef HEADER_BN_ARCH_H
+ #define HEADER_BN_ARCH_H
+-
++#if defined(_MSC_VER) && defined(_M_ARM64)
++
++#include <intrin.h>
++
++#define HAVE_BN_CT_NE_ZERO
++
++static inline int
++bn_ct_ne_zero(BN_ULONG w)
++{
++	return 1U ^ (_CountLeadingZeros64((unsigned __int64)w) >> 6);
++}
++
++#endif
++
+ #ifndef OPENSSL_NO_ASM
-- 
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