diff --git a/utils/TableGen/IntrinsicEmitter.cpp b/utils/TableGen/IntrinsicEmitter.cpp
index 0642f59ace5..9630c926ac5 100644
--- a/utils/TableGen/IntrinsicEmitter.cpp
+++ b/utils/TableGen/IntrinsicEmitter.cpp
@@ -466,7 +466,9 @@ static void EncodeFixedValueType(MVT::SimpleValueType VT,
   Sig.push_back(~0U);
 }
 
+#ifdef _MSC_VER
 #pragma optimize("",off) // MSVC 2010 optimizer can't deal with this function.
+#endif 
 
 static void EncodeFixedType(Record *R, SmallVectorImpl<unsigned> &Sig) {
   
@@ -532,7 +534,10 @@ static void EncodeFixedType(Record *R, SmallVectorImpl<unsigned> &Sig) {
   assert(VT != MVT::isVoid);
   EncodeFixedValueType(VT, Sig);
 }
+
+#ifdef _MSC_VER
 #pragma optimize("",on)
+#endif
 
 /// ComputeFixedEncoding - If we can encode the type signature for this
 /// intrinsic into 32 bits, return it.  If not, return ~0U.