diff --git a/llvm-build/build.py b/llvm-build/build.py
index 3931e28a744a99416402ba7b54ba33aa75a411fc..84d159b1444ca7e0268d1898009c9e875a9c1671 100755
--- a/llvm-build/build.py
+++ b/llvm-build/build.py
@@ -775,7 +775,7 @@ class LlvmCore(BuildUtils):
                           env=env)
 
         # First of all build compiler-rt because it's needed to be built before libunwind and etc.
-        if not self.build_config.build_only and not self.use_platform().startswith('windows'):
+        if not self.build_config.build_only and not 'windows-x86_64' in build_dir:
             self.invoke_ninja(out_path=build_dir,
                               env=env,
                               target=["compiler-rt"],