[X86][SSE] combineToExtendVectorInReg - add ANY_EXTEND support TODO. NFCI.

So I don't forget - there's a load of yak shaving to do first.

llvm-svn: 363847

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -41345,6 +41345,7 @@ static SDValue combineToExtendVectorInReg(SDNode *N, SelectionDAG &DAG,
     return SDValue();
 
   unsigned Opcode = N->getOpcode();
+  // TODO - add ANY_EXTEND support.
   if (Opcode != ISD::SIGN_EXTEND && Opcode != ISD::ZERO_EXTEND)
     return SDValue();
   if (!DCI.isBeforeLegalizeOps())