From 1081a2d81829ce5b09adb9b30b9de6dec68a4274 Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@microsoft.com>
Date: Wed, 25 Feb 2026 08:12:00 -0800
Subject: [PATCH] Build the STL with only `/O2`, not `/Os`

---
 CMakeLists.txt                | 4 +---
 stl/src/vector_algorithms.cpp | 4 ----
 2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index afb6a97f978..4ae54d0071d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -105,9 +105,7 @@ if(STL_USE_ANALYZE)
 endif()
 
 set(VCLIBS_DEBUG_OPTIONS "$<$<COMPILE_LANGUAGE:CXX>:/Od>")
-
-# TRANSITION, GH-2108: Investigate building the STL with only /O2, not /Os.
-set(VCLIBS_RELEASE_OPTIONS "$<$<COMPILE_LANGUAGE:CXX>:/O2;/Os>")
+set(VCLIBS_RELEASE_OPTIONS "$<$<COMPILE_LANGUAGE:CXX>:/O2>")
 
 if(CONFIGURE_TESTING)
     add_subdirectory(tests)
diff --git a/stl/src/vector_algorithms.cpp b/stl/src/vector_algorithms.cpp
index 474d0fc1c9e..f896b8c635e 100644
--- a/stl/src/vector_algorithms.cpp
+++ b/stl/src/vector_algorithms.cpp
@@ -5,10 +5,6 @@
 #error _M_CEE_PURE should not be defined when compiling vector_algorithms.cpp.
 #endif
 
-#ifndef _DEBUG
-#pragma optimize("t", on) // TRANSITION, GH-2108: Override /Os with /Ot for this TU before any function definitions
-#endif
-
 #include <__msvc_minmax.hpp>
 #include <cstdint>
 #include <cstring>