SDAG: Implement Select instead of SelectImpl in MSP430DAGToDAGISel

- Where we were returning a node before, call ReplaceNode instead.
- Where we would return null to fall back to another selector, rename
  the method to try* and return a bool for success.
- Where we were calling SelectNodeTo, just return afterwards.

Part of llvm.org/pr26808.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269393 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 57 insertions, 76 deletions

diff --git a/lib/Target/MSP430/MSP430ISelDAGToDAG.cpp b/lib/Target/MSP430/MSP430ISelDAGToDAG.cpp
index 7119c3886e6..69c609d04b5 100644
--- a/lib/Target/MSP430/MSP430ISelDAGToDAG.cpp
+++ b/lib/Target/MSP430/MSP430ISelDAGToDAG.cpp
@@ -110,10 +110,10 @@ namespace {
   #include "MSP430GenDAGISel.inc"
 
   private:
-    SDNode *SelectImpl(SDNode *N) override;
-    SDNode *SelectIndexedLoad(SDNode *Op);
-    SDNode *SelectIndexedBinOp(SDNode *Op, SDValue N1, SDValue N2,
-                               unsigned Opc8, unsigned Opc16);
+    void Select(SDNode *N) override;
+    bool tryIndexedLoad(SDNode *Op);
+    bool tryIndexedBinOp(SDNode *Op, SDValue N1, SDValue N2, unsigned Opc8,
+                         unsigned Opc16);
 
     bool SelectAddr(SDValue Addr, SDValue &Base, SDValue &Disp);
   };
@@ -323,10 +323,10 @@ static bool isValidIndexedLoad(const LoadSDNode *LD) {
   return true;
 }
 
-SDNode *MSP430DAGToDAGISel::SelectIndexedLoad(SDNode *N) {
+bool MSP430DAGToDAGISel::tryIndexedLoad(SDNode *N) {
   LoadSDNode *LD = cast<LoadSDNode>(N);
   if (!isValidIndexedLoad(LD))
-    return nullptr;
+    return false;
 
   MVT VT = LD->getMemoryVT().getSimpleVT();
 
@@ -339,23 +339,23 @@ SDNode *MSP430DAGToDAGISel::SelectIndexedLoad(SDNode *N) {
     Opcode = MSP430::MOV16rm_POST;
     break;
   default:
-    return nullptr;
+    return false;
   }
 
-   return CurDAG->getMachineNode(Opcode, SDLoc(N),
-                                 VT, MVT::i16, MVT::Other,
-                                 LD->getBasePtr(), LD->getChain());
+  ReplaceNode(N,
+              CurDAG->getMachineNode(Opcode, SDLoc(N), VT, MVT::i16, MVT::Other,
+                                     LD->getBasePtr(), LD->getChain()));
+  return true;
 }
 
-SDNode *MSP430DAGToDAGISel::SelectIndexedBinOp(SDNode *Op,
-                                               SDValue N1, SDValue N2,
-                                               unsigned Opc8, unsigned Opc16) {
+bool MSP430DAGToDAGISel::tryIndexedBinOp(SDNode *Op, SDValue N1, SDValue N2,
+                                         unsigned Opc8, unsigned Opc16) {
   if (N1.getOpcode() == ISD::LOAD &&
       N1.hasOneUse() &&
       IsLegalToFold(N1, Op, Op, OptLevel)) {
     LoadSDNode *LD = cast<LoadSDNode>(N1);
     if (!isValidIndexedLoad(LD))
-      return nullptr;
+      return false;
 
     MVT VT = LD->getMemoryVT().getSimpleVT();
     unsigned Opc = (VT == MVT::i16 ? Opc16 : Opc8);
@@ -369,14 +369,14 @@ SDNode *MSP430DAGToDAGISel::SelectIndexedBinOp(SDNode *Op,
     ReplaceUses(SDValue(N1.getNode(), 2), SDValue(ResNode, 2));
     // Transfer writeback.
     ReplaceUses(SDValue(N1.getNode(), 1), SDValue(ResNode, 1));
-    return ResNode;
+    return true;
   }
 
-  return nullptr;
+  return false;
 }
 
 
-SDNode *MSP430DAGToDAGISel::SelectImpl(SDNode *Node) {
+void MSP430DAGToDAGISel::Select(SDNode *Node) {
   SDLoc dl(Node);
 
   // Dump information about the Node being selected
@@ -390,7 +390,7 @@ SDNode *MSP430DAGToDAGISel::SelectImpl(SDNode *Node) {
           Node->dump(CurDAG);
           errs() << "\n");
     Node->setNodeId(-1);
-    return nullptr;
+    return;
   }
 
   // Few custom selection stuff.
@@ -400,89 +400,70 @@ SDNode *MSP430DAGToDAGISel::SelectImpl(SDNode *Node) {
     assert(Node->getValueType(0) == MVT::i16);
     int FI = cast<FrameIndexSDNode>(Node)->getIndex();
     SDValue TFI = CurDAG->getTargetFrameIndex(FI, MVT::i16);
-    if (Node->hasOneUse())
-      return CurDAG->SelectNodeTo(Node, MSP430::ADD16ri, MVT::i16, TFI,
-                                  CurDAG->getTargetConstant(0, dl, MVT::i16));
-    return CurDAG->getMachineNode(MSP430::ADD16ri, dl, MVT::i16, TFI,
-                                  CurDAG->getTargetConstant(0, dl, MVT::i16));
+    if (Node->hasOneUse()) {
+      CurDAG->SelectNodeTo(Node, MSP430::ADD16ri, MVT::i16, TFI,
+                           CurDAG->getTargetConstant(0, dl, MVT::i16));
+      return;
+    }
+    ReplaceNode(Node, CurDAG->getMachineNode(
+                          MSP430::ADD16ri, dl, MVT::i16, TFI,
+                          CurDAG->getTargetConstant(0, dl, MVT::i16)));
+    return;
   }
   case ISD::LOAD:
-    if (SDNode *ResNode = SelectIndexedLoad(Node))
-      return ResNode;
+    if (tryIndexedLoad(Node))
+      return;
     // Other cases are autogenerated.
     break;
   case ISD::ADD:
-    if (SDNode *ResNode =
-        SelectIndexedBinOp(Node,
-                           Node->getOperand(0), Node->getOperand(1),
-                           MSP430::ADD8rm_POST, MSP430::ADD16rm_POST))
-      return ResNode;
-    else if (SDNode *ResNode =
-             SelectIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
-                                MSP430::ADD8rm_POST, MSP430::ADD16rm_POST))
-      return ResNode;
+    if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
+                        MSP430::ADD8rm_POST, MSP430::ADD16rm_POST))
+      return;
+    else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
+                             MSP430::ADD8rm_POST, MSP430::ADD16rm_POST))
+      return;
 
     // Other cases are autogenerated.
     break;
   case ISD::SUB:
-    if (SDNode *ResNode =
-        SelectIndexedBinOp(Node,
-                           Node->getOperand(0), Node->getOperand(1),
-                           MSP430::SUB8rm_POST, MSP430::SUB16rm_POST))
-      return ResNode;
+    if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
+                        MSP430::SUB8rm_POST, MSP430::SUB16rm_POST))
+      return;
 
     // Other cases are autogenerated.
     break;
   case ISD::AND:
-    if (SDNode *ResNode =
-        SelectIndexedBinOp(Node,
-                           Node->getOperand(0), Node->getOperand(1),
-                           MSP430::AND8rm_POST, MSP430::AND16rm_POST))
-      return ResNode;
-    else if (SDNode *ResNode =
-             SelectIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
-                                MSP430::AND8rm_POST, MSP430::AND16rm_POST))
-      return ResNode;
+    if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
+                        MSP430::AND8rm_POST, MSP430::AND16rm_POST))
+      return;
+    else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
+                             MSP430::AND8rm_POST, MSP430::AND16rm_POST))
+      return;
 
     // Other cases are autogenerated.
     break;
   case ISD::OR:
-    if (SDNode *ResNode =
-        SelectIndexedBinOp(Node,
-                           Node->getOperand(0), Node->getOperand(1),
-                           MSP430::OR8rm_POST, MSP430::OR16rm_POST))
-      return ResNode;
-    else if (SDNode *ResNode =
-             SelectIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
-                                MSP430::OR8rm_POST, MSP430::OR16rm_POST))
-      return ResNode;
+    if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
+                        MSP430::OR8rm_POST, MSP430::OR16rm_POST))
+      return;
+    else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
+                             MSP430::OR8rm_POST, MSP430::OR16rm_POST))
+      return;
 
     // Other cases are autogenerated.
     break;
   case ISD::XOR:
-    if (SDNode *ResNode =
-        SelectIndexedBinOp(Node,
-                           Node->getOperand(0), Node->getOperand(1),
-                           MSP430::XOR8rm_POST, MSP430::XOR16rm_POST))
-      return ResNode;
-    else if (SDNode *ResNode =
-             SelectIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
-                                MSP430::XOR8rm_POST, MSP430::XOR16rm_POST))
-      return ResNode;
+    if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
+                        MSP430::XOR8rm_POST, MSP430::XOR16rm_POST))
+      return;
+    else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
+                             MSP430::XOR8rm_POST, MSP430::XOR16rm_POST))
+      return;
 
     // Other cases are autogenerated.
     break;
   }
 
   // Select the default instruction
-  SDNode *ResNode = SelectCode(Node);
-
-  DEBUG(errs() << "=> ");
-  if (ResNode == nullptr || ResNode == Node)
-    DEBUG(Node->dump(CurDAG));
-  else
-    DEBUG(ResNode->dump(CurDAG));
-  DEBUG(errs() << "\n");
-
-  return ResNode;
+  SelectCode(Node);
 }