diff --git a/clang-tools-extra/clangd/quality/CompletionModelCodegen.py b/clang-tools-extra/clangd/quality/CompletionModelCodegen.py
--- a/clang-tools-extra/clangd/quality/CompletionModelCodegen.py
+++ b/clang-tools-extra/clangd/quality/CompletionModelCodegen.py
@@ -145,6 +145,7 @@
     return """#ifndef %s
 #define %s
 #include <cstdint>
+#include "llvm/Support/Compiler.h"
 
 %s
 class %s {
@@ -160,6 +161,9 @@
   friend float Evaluate(const %s&);
 };
 
+// The function may have large number of lines of code. MSAN
+// build times out in such case.
+LLVM_NO_SANITIZE("memory")
 float Evaluate(const %s&);
 %s
 #endif // %s