From b9c33c32292d0ae5da2d75623a84a0e7796a2b63 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Wed, 9 Jul 2008 23:03:14 +0000
Subject: [PATCH] Simplify hasNUsesOfValue and hasAnyUsesOfValue even more.
 This makes their special-case checks of use_size() less beneficial, so remove
 them. This eliminates all but one use of use_size(), which is in
 AssignTopologicalOrder, which uses it only once for each node, and so can
 reasonably afford to recompute it, as this allows the UsesSize field of
 SDNode to be removed altogether.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53377 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/CodeGen/SelectionDAGNodes.h  | 21 +++++++--------------
 lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 16 ++--------------
 2 files changed, 9 insertions(+), 28 deletions(-)

diff --git a/include/llvm/CodeGen/SelectionDAGNodes.h b/include/llvm/CodeGen/SelectionDAGNodes.h
index 16b406c0a58..745a9b6dfc4 100644
--- a/include/llvm/CodeGen/SelectionDAGNodes.h
+++ b/include/llvm/CodeGen/SelectionDAGNodes.h
@@ -1048,9 +1048,6 @@ private:
   /// NumOperands/NumValues - The number of entries in the Operand/Value list.
   unsigned short NumOperands, NumValues;
   
-  /// UsesSize - The size of the uses list.
-  unsigned UsesSize;
-
   /// Uses - List of uses for this SDNode.
   SDUse *Uses;
 
@@ -1075,9 +1072,11 @@ public:
     return NodeType - ISD::BUILTIN_OP_END;
   }
 
-  size_t use_size() const { return UsesSize; }
+  size_t use_size() const { return std::distance(use_begin(), use_end()); }
   bool use_empty() const { return Uses == NULL; }
-  bool hasOneUse() const { return use_size() == 1; }
+  bool hasOneUse() const {
+    return !use_empty() && next(use_begin()) == use_end();
+  }
 
   /// getNodeId - Return the unique node id.
   ///
@@ -1249,7 +1248,7 @@ protected:
   }
 
   SDNode(unsigned Opc, SDVTList VTs, const SDOperand *Ops, unsigned NumOps)
-    : NodeType(Opc), NodeId(-1), UsesSize(0), Uses(NULL) {
+    : NodeType(Opc), NodeId(-1), Uses(NULL) {
     OperandsNeedDelete = true;
     NumOperands = NumOps;
     OperandList = NumOps ? new SDUse[NumOperands] : 0;
@@ -1258,7 +1257,6 @@ protected:
       OperandList[i] = Ops[i];
       OperandList[i].setUser(this);
       Ops[i].Val->addUse(OperandList[i]);
-      ++Ops[i].Val->UsesSize;
     }
     
     ValueList = VTs.VTs;
@@ -1266,7 +1264,7 @@ protected:
   }
 
   SDNode(unsigned Opc, SDVTList VTs, const SDUse *Ops, unsigned NumOps)
-    : NodeType(Opc), NodeId(-1), UsesSize(0), Uses(NULL) {
+    : NodeType(Opc), NodeId(-1), Uses(NULL) {
     OperandsNeedDelete = true;
     NumOperands = NumOps;
     OperandList = NumOps ? new SDUse[NumOperands] : 0;
@@ -1275,7 +1273,6 @@ protected:
       OperandList[i] = Ops[i];
       OperandList[i].setUser(this);
       Ops[i].getSDOperand().Val->addUse(OperandList[i]);
-      ++Ops[i].getSDOperand().Val->UsesSize;
     }
     
     ValueList = VTs.VTs;
@@ -1283,7 +1280,7 @@ protected:
   }
 
   SDNode(unsigned Opc, SDVTList VTs)
-    : NodeType(Opc), NodeId(-1), UsesSize(0), Uses(NULL) {
+    : NodeType(Opc), NodeId(-1), Uses(NULL) {
     OperandsNeedDelete = false;  // Operands set with InitOperands.
     NumOperands = 0;
     OperandList = 0;
@@ -1298,13 +1295,11 @@ protected:
     assert(OperandList == 0 && "Operands already set!");
     NumOperands = NumOps;
     OperandList = Ops;
-    UsesSize = 0;
     Uses = NULL;
     
     for (unsigned i = 0; i != NumOps; ++i) {
       OperandList[i].setUser(this);
       Ops[i].getVal()->addUse(OperandList[i]);
-      ++Ops[i].getVal()->UsesSize;
     }
   }
 
@@ -1323,14 +1318,12 @@ protected:
   void addUser(unsigned i, SDNode *User) {
     assert(User->OperandList[i].getUser() && "Node without parent");
     addUse(User->OperandList[i]);
-    ++UsesSize;
   }
 
   void removeUser(unsigned i, SDNode *User) {
     assert(User->OperandList[i].getUser() && "Node without parent");
     SDUse &Op = User->OperandList[i];
     Op.removeFromList();
-    --UsesSize;
   }
 };
 
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 0eb92967555..d98f1fa215a 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -3749,7 +3749,6 @@ void SDNode::MorphNodeTo(unsigned Opc, SDVTList L,
     OperandList[i].setUser(this);
     SDNode *N = OperandList[i].getVal();
     N->addUser(i, this);
-    ++N->UsesSize;
     DeadNodeSet.erase(N);
   }
 
@@ -4394,16 +4393,9 @@ const MVT *SDNode::getValueTypeList(MVT VT) {
 bool SDNode::hasNUsesOfValue(unsigned NUses, unsigned Value) const {
   assert(Value < getNumValues() && "Bad value!");
 
-  // If there is only one value, this is easy.
-  if (getNumValues() == 1)
-    return use_size() == NUses;
-  if (use_size() < NUses) return false;
-
-  SDOperand TheValue(const_cast<SDNode *>(this), Value);
-
   // TODO: Only iterate over uses of a given value of the node
   for (SDNode::use_iterator UI = use_begin(), E = use_end(); UI != E; ++UI) {
-    if (*UI == TheValue) {
+    if (UI->getSDOperand().ResNo == Value) {
       if (NUses == 0)
         return false;
       --NUses;
@@ -4420,12 +4412,8 @@ bool SDNode::hasNUsesOfValue(unsigned NUses, unsigned Value) const {
 bool SDNode::hasAnyUseOfValue(unsigned Value) const {
   assert(Value < getNumValues() && "Bad value!");
 
-  if (use_empty()) return false;
-
-  SDOperand TheValue(const_cast<SDNode *>(this), Value);
-
   for (SDNode::use_iterator UI = use_begin(), E = use_end(); UI != E; ++UI)
-    if (UI->getSDOperand() == TheValue)
+    if (UI->getSDOperand().ResNo == Value)
       return true;
 
   return false;