[llvm] Revert "[cmake] Fix VSINSTALLDIR check in FindDIASDK module (#208524)" (PR #209137)

[Charles Zablit via llvm-commits]

https://github.com/charles-zablit created https://github.com/llvm/llvm-project/pull/209137

This reverts commit 4c5e15667fe384e434961fe44cf5950dc309fdf1.

>From 01290c75519d6952675cc48ca372f2e6c93152b7 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Mon, 13 Jul 2026 12:01:17 +0100
Subject: [PATCH] Revert "[cmake] Fix VSINSTALLDIR check in FindDIASDK module
 (#208524)"

This reverts commit 4c5e15667fe384e434961fe44cf5950dc309fdf1.
---
 llvm/cmake/modules/FindDIASDK.cmake | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/cmake/modules/FindDIASDK.cmake b/llvm/cmake/modules/FindDIASDK.cmake
index 6b38260beba89..f3133d29de3b2 100644
--- a/llvm/cmake/modules/FindDIASDK.cmake
+++ b/llvm/cmake/modules/FindDIASDK.cmake
@@ -21,7 +21,7 @@ endif()
 if(LLVM_WINSYSROOT)
   set(MSVC_DIA_SDK_DIR "${LLVM_WINSYSROOT}/DIA SDK" CACHE PATH
       "Path to the DIA SDK")
-elseif(DEFINED ENV{VSINSTALLDIR})
+elseif($ENV{VSINSTALLDIR})
   set(MSVC_DIA_SDK_DIR "$ENV{VSINSTALLDIR}DIA SDK" CACHE PATH
       "Path to the DIA SDK")
 elseif(NOT DEFINED MSVC_DIA_SDK_DIR)