diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -269,11 +269,6 @@
   message(FATAL_ERROR "LIBCXX_BUILD_32_BITS is not supported anymore when building the runtimes, please specify a full triple instead.")
 endif()
 
-# TODO: Remove this after branching for LLVM 15
-if(LIBCXX_SYSROOT OR LIBCXX_TARGET_TRIPLE OR LIBCXX_GCC_TOOLCHAIN)
-  message(WARNING "LIBCXX_SYSROOT, LIBCXX_TARGET_TRIPLE and LIBCXX_GCC_TOOLCHAIN are not supported anymore, please use the native CMake equivalents instead")
-endif()
-
 # Feature options -------------------------------------------------------------
 option(LIBCXX_ENABLE_EXCEPTIONS "Use exceptions." ON)
 option(LIBCXX_ENABLE_RTTI "Use run time type information." ON)