From: Devang Patel <dpatel@apple.com>
Date: Tue, 12 Jun 2007 00:14:41 +0000 (+0000)
Subject: Maintain DFS number in DomTreeNode itself.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3726b82a55a1864c2f9af86beaaeb2e1f3fbc99b;p=oota-llvm.git

Maintain DFS number in DomTreeNode itself.
This means now ETNodes are not useful anymore.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37546 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/Analysis/Dominators.h b/include/llvm/Analysis/Dominators.h
index 755407b40d9..f2d6da53e1e 100644
--- a/include/llvm/Analysis/Dominators.h
+++ b/include/llvm/Analysis/Dominators.h
@@ -65,6 +65,8 @@ class DomTreeNode {
   DomTreeNode *IDom;
   ETNode *ETN;
   std::vector<DomTreeNode*> Children;
+  int DFSNumIn, DFSNumOut;
+
 public:
   typedef std::vector<DomTreeNode*>::iterator iterator;
   typedef std::vector<DomTreeNode*>::const_iterator const_iterator;
@@ -80,12 +82,22 @@ public:
   inline const std::vector<DomTreeNode*> &getChildren() const { return Children; }
   
   inline DomTreeNode(BasicBlock *BB, DomTreeNode *iDom, ETNode *E) 
-    : TheBB(BB), IDom(iDom), ETN(E) {
+    : TheBB(BB), IDom(iDom), ETN(E), DFSNumIn(-1), DFSNumOut(-1) {
     if (IDom)
       ETN->setFather(IDom->getETNode());
   }
   inline DomTreeNode *addChild(DomTreeNode *C) { Children.push_back(C); return C; }
   void setIDom(DomTreeNode *NewIDom);
+
+  // Return true if this node is dominated by other. Use this only if DFS info is valid.
+  bool DominatedBy(const DomTreeNode *other) const {
+    return this->DFSNumIn >= other->DFSNumIn &&
+      this->DFSNumOut <= other->DFSNumOut;
+  }
+
+  /// assignDFSNumber - Assign In and Out numbers while walking dominator tree
+  /// in dfs order.
+  void assignDFSNumber(int num);
 };
 
 //===----------------------------------------------------------------------===//
@@ -214,14 +226,16 @@ protected:
     ETNode *NodeB = B->getETNode();
     
     if (DFSInfoValid)
-      return NodeB->DominatedBy(NodeA);
+      return B->DominatedBy(A);
+      //return NodeB->DominatedBy(NodeA);
 
     // If we end up with too many slow queries, just update the
     // DFS numbers on the theory that we are going to keep querying.
     SlowQueries++;
     if (SlowQueries > 32) {
       updateDFSNumbers();
-      return NodeB->DominatedBy(NodeA);
+      return B->DominatedBy(A);
+      //return NodeB->DominatedBy(NodeA);
     }
     //return NodeB->DominatedBySlow(NodeA);
     return dominatedBySlowTreeWalk(A, B);
diff --git a/lib/VMCore/Dominators.cpp b/lib/VMCore/Dominators.cpp
index 8b2c1a45e22..225d8d200ae 100644
--- a/lib/VMCore/Dominators.cpp
+++ b/lib/VMCore/Dominators.cpp
@@ -319,9 +319,11 @@ void DominatorTreeBase::updateDFSNumbers()
       BasicBlock *BB = *I;
       DomTreeNode *BBNode = getNode(BB);
       if (BBNode) {
-        ETNode *ETN = BBNode->getETNode();
-        if (ETN && !ETN->hasFather())
-          ETN->assignDFSNumber(dfsnum);
+        if (!BBNode->getIDom())
+          BBNode->assignDFSNumber(dfsnum);
+        //ETNode *ETN = BBNode->getETNode();
+        //if (ETN && !ETN->hasFather())
+        //  ETN->assignDFSNumber(dfsnum);
       }
   }
   SlowQueries = 0;
@@ -414,6 +416,38 @@ BasicBlock *DominatorTreeBase::findNearestCommonDominator(BasicBlock *A, BasicBl
   return NULL;
 }
 
+/// assignDFSNumber - Assign In and Out numbers while walking dominator tree
+/// in dfs order.
+void DomTreeNode::assignDFSNumber(int num) {
+  std::vector<DomTreeNode *>  workStack;
+  std::set<DomTreeNode *> visitedNodes;
+  
+  workStack.push_back(this);
+  visitedNodes.insert(this);
+  this->DFSNumIn = num++;
+  
+  while (!workStack.empty()) {
+    DomTreeNode  *Node = workStack.back();
+    
+    bool visitChild = false;
+    for (std::vector<DomTreeNode*>::iterator DI = Node->begin(),
+           E = Node->end(); DI != E && !visitChild; ++DI) {
+      DomTreeNode *Child = *DI;
+      if (visitedNodes.count(Child) == 0) {
+        visitChild = true;
+        Child->DFSNumIn = num++;
+        workStack.push_back(Child);
+        visitedNodes.insert(Child);
+      }
+    }
+    if (!visitChild) {
+      // If we reach here means all children are visited
+      Node->DFSNumOut = num++;
+      workStack.pop_back();
+    }
+  }
+}
+
 void DomTreeNode::setIDom(DomTreeNode *NewIDom) {
   assert(IDom && "No immediate dominator?");
   if (IDom != NewIDom) {