Index: llvm-toolchain-18_18.1.2/compiler-rt/lib/builtins/CMakeLists.txt
===================================================================
--- llvm-toolchain-18_18.1.2.orig/compiler-rt/lib/builtins/CMakeLists.txt
+++ llvm-toolchain-18_18.1.2/compiler-rt/lib/builtins/CMakeLists.txt
@@ -772,6 +772,12 @@ else ()
     append_list_if(COMPILER_RT_ENABLE_CET -fcf-protection=full BUILTIN_CFLAGS)
   endif()
 
+  if(${CMAKE_SYSTEM_PROCESSOR} MATCHES "x86_64")
+    append_list_if(COMPILER_RT_HAS_FLOAT16 -msse2 -DCOMPILER_RT_HAS_FLOAT16 BUILTIN_CFLAGS)
+  else ()
+    append_list_if(COMPILER_RT_HAS_FLOAT16 -DCOMPILER_RT_HAS_FLOAT16 BUILTIN_CFLAGS)
+  endif()
+
   append_list_if(COMPILER_RT_HAS_STD_C11_FLAG -std=c11 BUILTIN_CFLAGS)
   append_list_if(COMPILER_RT_HAS_WBUILTIN_DECLARATION_MISMATCH_FLAG -Werror=builtin-declaration-mismatch BUILTIN_CFLAGS)