Revert the SelectionDAG optimization that makes

it impossible to create a MERGE_VALUES node with
only one result: sometimes it is useful to be able
to create a node with only one result out of one of
the results of a node with more than one result, for
example because the new node will eventually be used
to replace a one-result node using ReplaceAllUsesWith,
cf X86TargetLowering::ExpandFP_TO_SINT.  On the other
hand, most users of MERGE_VALUES don't need this and
for them the optimization was valuable.  So add a new
utility method getMergeValues for creating MERGE_VALUES
nodes which by default performs the optimization.
Change almost everywhere to use getMergeValues (and
tidy some stuff up at the same time).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52893 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 5 deletions

diff --git a/lib/Target/CellSPU/SPUISelLowering.cpp b/lib/Target/CellSPU/SPUISelLowering.cpp
index 41555c0..e99a8bd 100644
--- a/lib/Target/CellSPU/SPUISelLowering.cpp
+++ b/lib/Target/CellSPU/SPUISelLowering.cpp
@@ -1060,9 +1060,8 @@ LowerFORMAL_ARGUMENTS(SDOperand Op, SelectionDAG &DAG, int &VarArgsFrameIndex)
   ArgValues.push_back(Root);
  
   // Return the new list of results.
-  std::vector<MVT> RetVT(Op.Val->value_begin(),
-                                    Op.Val->value_end());
-  return DAG.getNode(ISD::MERGE_VALUES, RetVT, &ArgValues[0], ArgValues.size());
+  return DAG.getMergeValues(Op.Val->getVTList(), &ArgValues[0],
+                            ArgValues.size());
 }
 
 /// isLSAAddress - Return the immediate to use if the specified
@@ -1301,8 +1300,8 @@ LowerCALL(SDOperand Op, SelectionDAG &DAG, const SPUSubtarget *ST) {
   
   // Otherwise, merge everything together with a MERGE_VALUES node.
   ResultVals[NumResults++] = Chain;
-  SDOperand Res = DAG.getNode(ISD::MERGE_VALUES, NodeTys,
-                              ResultVals, NumResults);
+  SDOperand Res = DAG.getMergeValues(DAG.getVTList(&NodeTys[0], NodeTys.size()),
+                                     ResultVals, NumResults);
   return Res.getValue(Op.ResNo);
 }