From acac7d4b21d0477ae8d3cf991d88b19ecf495588 Mon Sep 17 00:00:00 2001
From: Steve Dower <steve.dower@python.org>
Date: Sun, 20 Sep 2026 08:31:17 +0100
Subject: [PATCH 1/4] gh-153668: Temporarily disable unicodectype.c
 optimization on WinARM64 due to compiler bug (#153669)

* Only disable during Release (not PGO)

* Update PCbuild/pyproject.props

---------

Co-authored-by: Chris Eibl <138194463+chris-eibl@users.noreply.github.com>
(cherry picked from commit 9ea05d4b8f8a007d57b2b33a4dec26408fe6836b)

# Conflicts:
#	PCbuild/pythoncore.vcxproj
---
 PCbuild/pyproject.props    | 2 ++
 PCbuild/pythoncore.vcxproj | 5 ++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/PCbuild/pyproject.props b/PCbuild/pyproject.props
index 53bfe5e3ea95ccf..17d4773367047f2 100644
--- a/PCbuild/pyproject.props
+++ b/PCbuild/pyproject.props
@@ -38,6 +38,8 @@
     <!-- See https://developercommunity.visualstudio.com/t/Regression-in-MSVC-1433-1434-ARM64-co/10224361 -->
     <MSVCHasBrokenARM64Clamping Condition="$(_VCToolsVersion) == '14.34' or $(_VCToolsVersion) == '14.35'">true</MSVCHasBrokenARM64Clamping>
     <MSVCHasBrokenARM64SignExtension Condition="$(_VCToolsVersion) == '14.37'">true</MSVCHasBrokenARM64SignExtension>
+    <!-- See gh-153668 and https://developercommunity.visualstudio.com/t/ARM64-compiler-uses-excessive-memory-on/11120089 -->
+    <MSVCHasBrokenARM64UniDbOpt Condition="$(_VCToolsVersion) == '14.50' or $(_VCToolsVersion) == '14.51'">true</MSVCHasBrokenARM64UniDbOpt>
   </PropertyGroup>
 
   <PropertyGroup>
diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj
index 69d83764fbe94bd..5099e44020ec500 100644
--- a/PCbuild/pythoncore.vcxproj
+++ b/PCbuild/pythoncore.vcxproj
@@ -555,7 +555,10 @@
     <ClCompile Include="..\Objects\tupleobject.c" />
     <ClCompile Include="..\Objects\typeobject.c" />
     <ClCompile Include="..\Objects\typevarobject.c" />
-    <ClCompile Include="..\Objects\unicodectype.c" />
+    <ClCompile Include="..\Objects\unicodectype.c">
+      <!-- gh-153668: Temporarily disabled due to a compiler bug -->
+      <Optimization Condition="$(Platform) == 'ARM64' and $(Configuration) == 'Release' and $(MSVCHasBrokenARM64UniDbOpt) == 'true'">Disabled</Optimization>
+    </ClCompile>
     <ClCompile Include="..\Objects\unicodeobject.c" />
     <ClCompile Include="..\Objects\unionobject.c" />
     <ClCompile Include="..\Objects\weakrefobject.c" />

From b08e5592c70039ba40e515e6b9e29fb7c610fbff Mon Sep 17 00:00:00 2001
From: Chris Eibl <138194463+chris-eibl@users.noreply.github.com>
Date: Sat, 26 Sep 2026 09:07:01 +0200
Subject: [PATCH 2/4] dummy edit to trigger MSI CI

---
 Tools/msi/bundle/bootstrap/pythonba.vcxproj | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Tools/msi/bundle/bootstrap/pythonba.vcxproj b/Tools/msi/bundle/bootstrap/pythonba.vcxproj
index 4b38582f0d31e51..4ec1958d74dd5cb 100644
--- a/Tools/msi/bundle/bootstrap/pythonba.vcxproj
+++ b/Tools/msi/bundle/bootstrap/pythonba.vcxproj
@@ -1,4 +1,5 @@
-<?xml version="1.0" encoding="utf-8"?>
+<!-- dummy edit to trigger MSI CI -->
+<?xml version="1.0" encoding="utf-8"?>
 <!--
   <copyright file="wixstdba.vcxproj" company="Outercurve Foundation">
     Copyright (c) 2004, Outercurve Foundation.

From e2087c4fe61de7130e61d04153da719f913ae16b Mon Sep 17 00:00:00 2001
From: Chris Eibl <138194463+chris-eibl@users.noreply.github.com>
Date: Sat, 26 Sep 2026 09:28:33 +0200
Subject: [PATCH 3/4] dummy edit, 2nd attempt

---
 Tools/msi/bundle/bootstrap/pythonba.vcxproj | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Tools/msi/bundle/bootstrap/pythonba.vcxproj b/Tools/msi/bundle/bootstrap/pythonba.vcxproj
index 4ec1958d74dd5cb..559678816352394 100644
--- a/Tools/msi/bundle/bootstrap/pythonba.vcxproj
+++ b/Tools/msi/bundle/bootstrap/pythonba.vcxproj
@@ -1,11 +1,12 @@
-<!-- dummy edit to trigger MSI CI -->
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <!--
   <copyright file="wixstdba.vcxproj" company="Outercurve Foundation">
     Copyright (c) 2004, Outercurve Foundation.
     This software is released under Microsoft Reciprocal License (MS-RL).
     The license and further copyright text can be found in the file
     LICENSE.TXT at the root directory of the distribution.
+
+    Dummy edit to trigger CI
   </copyright>
 -->
 <Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">

From 4a12085b09e5ccc527c2f46eb1680750ff7896ef Mon Sep 17 00:00:00 2001
From: Chris Eibl <138194463+chris-eibl@users.noreply.github.com>
Date: Sat, 26 Sep 2026 09:58:57 +0200
Subject: [PATCH 4/4] remove dummy edit

---
 Tools/msi/bundle/bootstrap/pythonba.vcxproj | 2 --
 1 file changed, 2 deletions(-)

diff --git a/Tools/msi/bundle/bootstrap/pythonba.vcxproj b/Tools/msi/bundle/bootstrap/pythonba.vcxproj
index 559678816352394..4b38582f0d31e51 100644
--- a/Tools/msi/bundle/bootstrap/pythonba.vcxproj
+++ b/Tools/msi/bundle/bootstrap/pythonba.vcxproj
@@ -5,8 +5,6 @@
     This software is released under Microsoft Reciprocal License (MS-RL).
     The license and further copyright text can be found in the file
     LICENSE.TXT at the root directory of the distribution.
-
-    Dummy edit to trigger CI
   </copyright>
 -->
 <Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">