diff --git a/lib/VMCore/CMakeLists.txt b/lib/VMCore/CMakeLists.txt
index e1efcdadc71..ba6edd9f55d 100644
--- a/lib/VMCore/CMakeLists.txt
+++ b/lib/VMCore/CMakeLists.txt
@@ -36,3 +36,12 @@ add_llvm_library(LLVMCore
   ValueTypes.cpp
   Verifier.cpp
   )
+
+# Workaround: It takes over 20 minutes to compile with msvc10.
+# FIXME: Suppressing optimizations to core libraries would not be good thing.
+if( MSVC_VERSION EQUAL 1600 )
+set_property(
+  SOURCE Function.cpp
+  PROPERTY COMPILE_FLAGS "/Og-"
+  )
+endif()