Misc cleanup; addresses Duncan's comments on r138877.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138887 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp

@@ -110,9 +110,7 @@ SDValue DAGTypeLegalizer::SoftenFloatRes_BITCAST(SDNode *N) {
 
 SDValue DAGTypeLegalizer::SoftenFloatRes_MERGE_VALUES(SDNode *N) {
   SDValue Op = DecomposeMERGE_VALUES(N);
-  return Op.getValueType().isVector() ?
-      BitConvertVectorToIntegerVector(Op) :
-      BitConvertToInteger(Op);
+  return BitConvertToInteger(Op);
 }
 
 SDValue DAGTypeLegalizer::SoftenFloatRes_BUILD_PAIR(SDNode *N) {

lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp

@@ -139,8 +139,6 @@ void DAGTypeLegalizer::PromoteIntegerResult(SDNode *N, unsigned ResNo) {
 
 SDValue DAGTypeLegalizer::PromoteIntRes_MERGE_VALUES(SDNode *N) {
   SDValue Op = DecomposeMERGE_VALUES(N);
-  assert(Op.getValueType().isInteger()
-      && "Must decompose to an integer type!");
   return GetPromotedInteger(Op);
 }
 
@@ -1556,11 +1554,10 @@ void DAGTypeLegalizer::ExpandIntRes_ADDSUBE(SDNode *N,
   // use the new one.
   ReplaceValueWith(SDValue(N, 1), Hi.getValue(1));
 }
+
 void DAGTypeLegalizer::ExpandIntRes_MERGE_VALUES(SDNode *N, 
-                                          SDValue &Lo, SDValue &Hi) {
+                                                 SDValue &Lo, SDValue &Hi) {
   SDValue Res = DecomposeMERGE_VALUES(N);
-  assert(Res.getValueType().isInteger()
-      && "Cannot split a non-integer value.");
   SplitInteger(Res, Lo, Hi);
 }
 

lib/CodeGen/SelectionDAG/LegalizeTypes.cpp

@@ -948,21 +948,22 @@ bool DAGTypeLegalizer::CustomWidenLowerNode(SDNode *N, EVT VT) {
 
 SDValue DAGTypeLegalizer::DecomposeMERGE_VALUES(SDNode *N) {
   unsigned i;
-   // A MERGE_VALUES node can produce any number of values.
-   // We know that the first illegal type needs to be handled.
+  // A MERGE_VALUES node can produce any number of values.
+  // Replace the results other than the first illegal one with the
+  // corresponding input operands.
   for (i = 0; isTypeLegal(N->getValueType(i)); ++i)
     ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i)));
 
-  // The first illegal result must be the one that needs to be handled.
-  SDValue BadValue = N->getOperand(i);
+  // The first illegal result is the one which needs to be handled;
+  // type legalization legalizes values in order.
+  SDValue IllegalValue = N->getOperand(i);
 
-  // Legalize the rest of the results into the input operands whether they
-  // are legal or not.
+  // Continue replacing results.
   unsigned e = N->getNumValues();
   for (++i; i != e; ++i) 
     ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i)));
 
-  return BadValue;
+  return IllegalValue;
 }
 
 /// GetSplitDestVTs - Compute the VTs needed for the low/hi parts of a type

lib/CodeGen/SelectionDAG/LegalizeTypes.h

@@ -149,10 +149,9 @@ private:
   bool CustomLowerNode(SDNode *N, EVT VT, bool LegalizeResult);
   bool CustomWidenLowerNode(SDNode *N, EVT VT);
 
-  // DecomposeMERGE_VALUES  takes a SDNode and returns the first
-  // illegal operand that needs to be modified. 
-  // All other nodes are legalized, whether they are legal or not.
-  // The resulting SDValue needs to be modified to make it legal.
+  // DecomposeMERGE_VALUES takes a SDNode and returns the first
+  // illegal value. All other results are replaced with the
+  // corresponding input operand.
   SDValue DecomposeMERGE_VALUES(SDNode *N);
 
   SDValue GetVectorElementPointer(SDValue VecPtr, EVT EltVT, SDValue Index);
@@ -162,9 +161,9 @@ private:
                       const SDValue *Ops, unsigned NumOps, bool isSigned,
                       DebugLoc dl);
   
-	std::pair<SDValue, SDValue> ExpandChainLibCall(RTLIB::Libcall LC,
-									                               SDNode *Node, bool isSigned);
-	std::pair<SDValue, SDValue> ExpandAtomic(SDNode *Node);
+  std::pair<SDValue, SDValue> ExpandChainLibCall(RTLIB::Libcall LC,
+                                                 SDNode *Node, bool isSigned);
+  std::pair<SDValue, SDValue> ExpandAtomic(SDNode *Node);
 
   SDValue PromoteTargetBoolean(SDValue Bool, EVT VT);
   void ReplaceValueWith(SDValue From, SDValue To);