diff --git a/compiler-rt/cmake/Modules/CompilerRTUtils.cmake b/compiler-rt/cmake/Modules/CompilerRTUtils.cmake
--- a/compiler-rt/cmake/Modules/CompilerRTUtils.cmake
+++ b/compiler-rt/cmake/Modules/CompilerRTUtils.cmake
@@ -173,7 +173,13 @@
   elseif(__AARCH64)
     add_default_target_arch(aarch64)
   elseif(__X86_64)
-    add_default_target_arch(x86_64)
+    if(CMAKE_SIZEOF_VOID_P EQUAL "4")
+      add_default_target_arch(x32)
+    elseif(CMAKE_SIZEOF_VOID_P EQUAL "8")
+      add_default_target_arch(x86_64)
+    else()
+      message(FATAL_ERROR "Unsupported pointer size for X86_64")
+    endif()
   elseif(__I386)
     add_default_target_arch(i386)
   elseif(__MIPS64) # must be checked before __MIPS