[compiler-rt] Fix an MSVC build issue. (PR #111557)

[Eli Friedman via llvm-commits]

================
@@ -599,27 +599,29 @@ else()
   set(COMPILER_RT_LINK_OR_COPY copy)
 endif()
 
-foreach(pat cas swp ldadd ldclr ldeor ldset)
-  foreach(size 1 2 4 8 16)
-    foreach(model 1 2 3 4 5)
-      if(pat STREQUAL "cas" OR NOT size STREQUAL "16")
-        set(source_asm "${CMAKE_CURRENT_SOURCE_DIR}/aarch64/lse.S")
-        set(helper_asm "${OA_HELPERS_DIR}/outline_atomic_${pat}${size}_${model}.S")
-        add_custom_command(
-          OUTPUT "${helper_asm}"
-          COMMAND ${CMAKE_COMMAND} -E ${COMPILER_RT_LINK_OR_COPY} "${source_asm}" "${helper_asm}"
-          DEPENDS "${source_asm}"
-        )
-        set_source_files_properties("${helper_asm}"
-          PROPERTIES
-          COMPILE_DEFINITIONS "L_${pat};SIZE=${size};MODEL=${model}"
-          INCLUDE_DIRECTORIES "${CMAKE_CURRENT_SOURCE_DIR}"
-        )
-        list(APPEND aarch64_SOURCES "${helper_asm}")
-      endif()
-    endforeach(model)
-  endforeach(size)
-endforeach(pat)
+if(COMPILER_RT_HAS_ASM_LSE)
----------------
efriedma-quic wrote:

COMPILER_RT_HAS_ASM_LSE is not the right flag for this; it will turn off these files for other builds where they should be included.  If we really want to explicitly exclude MSVC, `if (NOT MSVC)` is the right check.

https://github.com/llvm/llvm-project/pull/111557