From 1cbd606db2f09c8e461e7ba08f014e433028cf4b Mon Sep 17 00:00:00 2001
From: Dylan Conway <dylan.conway567@gmail.com>
Date: Wed, 4 Feb 2026 20:39:57 -0800
Subject: [PATCH] fix: restore PROCESSOR_ARCHITECTURE after VS dev shell on
 ARM64

VS dev shell with -HostArch amd64 sets PROCESSOR_ARCHITECTURE=AMD64,
causing CMake to misdetect the system as x64 and use -march=haswell
on ARM64. Restore PROCESSOR_ARCHITECTURE=ARM64 after VS dev shell.
---
 scripts/vs-shell.ps1 | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/scripts/vs-shell.ps1 b/scripts/vs-shell.ps1
index 3537fcc5ca..ffbf5eecaa 100755
--- a/scripts/vs-shell.ps1
+++ b/scripts/vs-shell.ps1
@@ -39,6 +39,12 @@ if($env:VSINSTALLDIR -eq $null) {
     # -HostArch only accepts "x86" or "amd64" — even on native ARM64, use "amd64"
     $hostArch = if ($script:VsArch -eq "arm64") { "amd64" } else { $script:VsArch }
     . $vsShell -Arch $script:VsArch -HostArch $hostArch
+
+    # VS dev shell with -HostArch amd64 sets PROCESSOR_ARCHITECTURE=AMD64,
+    # which causes CMake to misdetect the system as x64. Restore it on ARM64.
+    if ($script:IsARM64) {
+      $env:PROCESSOR_ARCHITECTURE = "ARM64"
+    }
   } finally {
     Pop-Location
   }