DAG: Follow-up to r319692 check the truncates inputs have the same type

MatchRotate assumes the types of the types of LHS and RHS are equal,
which is always the case then they come from an OR node, but here
we're getting them from two different TRUNC nodes, so we have to check
the types.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319695 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/DAGCombiner.cpp

@@ -4653,7 +4653,8 @@ SDNode *DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS, const SDLoc &DL) {
   if (!HasROTL && !HasROTR) return nullptr;
 
   // Check for truncated rotate.
-  if (LHS.getOpcode() == ISD::TRUNCATE && RHS.getOpcode() == ISD::TRUNCATE) {
+  if (LHS.getOpcode() == ISD::TRUNCATE && RHS.getOpcode() == ISD::TRUNCATE &&
+      LHS.getOperand(0).getValueType() == RHS.getOperand(0).getValueType()) {
     assert(LHS.getValueType() == RHS.getValueType());
     if (SDNode *Rot = MatchRotate(LHS.getOperand(0), RHS.getOperand(0), DL)) {
       return DAG.getNode(ISD::TRUNCATE, SDLoc(LHS), LHS.getValueType(),