From ef2748a40a6fcd72e652932f4ff647fcf01e6dc6 Mon Sep 17 00:00:00 2001
From: Stanley5249 <seer852741@gmail.com>
Date: Mon, 3 Aug 2026 15:25:02 +0800
Subject: [PATCH] fix(cmake): only apply /MP to the MSVC compiler, not icx

The MSVC top-level generator/toolset check stays true for mixed
`cl`/`icx` SYCL builds (-DCMAKE_C_COMPILER=cl -DCMAKE_CXX_COMPILER=icx),
so the unconditional /MP added in #1438 leaks into the icx CXX
compile line. icx rejects /MP once offloading is enabled, breaking
every Windows SYCL build. Gate /MP on the per-language compiler ID
instead of the generator-level MSVC variable.
---
 CMakeLists.txt | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a003f400a..3c2b7b4a8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,10 +11,11 @@ endif()
 if (MSVC)
     add_compile_definitions(_CRT_SECURE_NO_WARNINGS)
     add_compile_definitions(_SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING)
+    # /MP is MSVC-only: icx rejects it outright once offloading is enabled.
     add_compile_options(
-        $<$<COMPILE_LANGUAGE:C>:/MP>
+        $<$<AND:$<COMPILE_LANGUAGE:C>,$<C_COMPILER_ID:MSVC>>:/MP>
         $<$<COMPILE_LANGUAGE:C>:/utf-8>
-        $<$<COMPILE_LANGUAGE:CXX>:/MP>
+        $<$<AND:$<COMPILE_LANGUAGE:CXX>,$<CXX_COMPILER_ID:MSVC>>:/MP>
         $<$<COMPILE_LANGUAGE:CXX>:/utf-8>
     )
 endif()