Add allnodes() iterator range to SelectionDAG. NFC.

SelectionDAG already had begin/end methods for iterating over all
the nodes, but didn't define an iterator_range for us in foreach
loops.

This adds such a method and uses it in some of the eligible places
throughout the backends.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242212 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/SelectionDAG.h

@@ -323,6 +323,14 @@ public:
     return AllNodes.size();
   }
 
+  iterator_range<allnodes_iterator> allnodes() {
+    return iterator_range<allnodes_iterator>(allnodes_begin(), allnodes_end());
+  }
+  iterator_range<allnodes_const_iterator> allnodes() const {
+    return iterator_range<allnodes_const_iterator>(allnodes_begin(),
+                                                   allnodes_end());
+  }
+
   /// Return the root tag of the SelectionDAG.
   const SDValue &getRoot() const { return Root; }
 

lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp

@@ -725,9 +725,8 @@ void ScheduleDAGLinearize::Schedule() {
 
   SmallVector<SDNode*, 8> Glues;
   unsigned DAGSize = 0;
-  for (SelectionDAG::allnodes_iterator I = DAG->allnodes_begin(),
+  for (SDNode &Node : DAG->allnodes()) {
-         E = DAG->allnodes_end(); I != E; ++I) {
+    SDNode *N = &Node;
-    SDNode *N = I;
 
     // Use node id to record degree.
     unsigned Degree = N->use_size();

lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp

@@ -289,9 +289,8 @@ void ScheduleDAGSDNodes::ClusterNeighboringLoads(SDNode *Node) {
 /// ClusterNodes - Cluster certain nodes which should be scheduled together.
 ///
 void ScheduleDAGSDNodes::ClusterNodes() {
-  for (SelectionDAG::allnodes_iterator NI = DAG->allnodes_begin(),
+  for (SDNode &NI : DAG->allnodes()) {
-       E = DAG->allnodes_end(); NI != E; ++NI) {
+    SDNode *Node = ∋
-    SDNode *Node = &*NI;
     if (!Node || !Node->isMachineOpcode())
       continue;
 
@@ -308,9 +307,8 @@ void ScheduleDAGSDNodes::BuildSchedUnits() {
   // to their associated SUnits by holding SUnits table indices. A value
   // of -1 means the SDNode does not yet have an associated SUnit.
   unsigned NumNodes = 0;
-  for (SelectionDAG::allnodes_iterator NI = DAG->allnodes_begin(),
+  for (SDNode &NI : DAG->allnodes()) {
-       E = DAG->allnodes_end(); NI != E; ++NI) {
+    NI.setNodeId(-1);
-    NI->setNodeId(-1);
     ++NumNodes;
   }
 

lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp

@@ -1371,18 +1371,14 @@ void AMDGPUDAGToDAGISel::PostprocessISelDAG() {
   do {
     IsModified = false;
     // Go over all selected nodes and try to fold them a bit more
-    for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(),
+    for (SDNode &Node : CurDAG->allnodes()) {
-         E = CurDAG->allnodes_end(); I != E; ++I) {
+      MachineSDNode *MachineNode = dyn_cast<MachineSDNode>(&Node);
-
-      SDNode *Node = I;
-
-      MachineSDNode *MachineNode = dyn_cast<MachineSDNode>(I);
       if (!MachineNode)
         continue;
 
       SDNode *ResNode = Lowering.PostISelFolding(MachineNode, *CurDAG);
-      if (ResNode != Node) {
+      if (ResNode != &Node) {
-        ReplaceUses(Node, ResNode);
+        ReplaceUses(&Node, ResNode);
         IsModified = true;
       }
     }

lib/Target/PowerPC/PPCISelDAGToDAG.cpp

@@ -3406,9 +3406,8 @@ void PPCDAGToDAGISel::PeepholeCROps() {
   bool IsModified;
   do {
     IsModified = false;
-    for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(),
+    for (SDNode &Node : CurDAG->allnodes()) {
-         E = CurDAG->allnodes_end(); I != E; ++I) {
+      MachineSDNode *MachineNode = dyn_cast<MachineSDNode>(&Node);
-      MachineSDNode *MachineNode = dyn_cast<MachineSDNode>(I);
       if (!MachineNode || MachineNode->use_empty())
         continue;
       SDNode *ResNode = MachineNode;