Start using the new function cloning header

[oota-llvm.git] / lib / Analysis / LoopInfo.cpp

diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp
index 8988877dc4b77f81bb4c9c871a42478b50b22f74..002e55362452a7da852adfee2137af56decbf606 100644 (file)
--- a/lib/Analysis/LoopInfo.cpp
+++ b/lib/Analysis/LoopInfo.cpp
@@ -16,7 +16,6 @@
 
 static RegisterAnalysis<LoopInfo>
 X("loops", "Natural Loop Construction", true);
-AnalysisID LoopInfo::ID = X;
 
 //===----------------------------------------------------------------------===//
 // Loop implementation
@@ -25,6 +24,30 @@ bool Loop::contains(const BasicBlock *BB) const {
   return find(Blocks.begin(), Blocks.end(), BB) != Blocks.end();
 }
 
+bool Loop::isLoopExit(const BasicBlock *BB) const {
+  for (BasicBlock::succ_const_iterator SI = succ_begin(BB), SE = succ_end(BB);
+       SI != SE; ++SI) {
+    if (! contains(*SI))
+      return true;
+  }
+  return false;
+}
+
+unsigned Loop::getNumBackEdges() const {
+  unsigned numBackEdges = 0;
+  BasicBlock *header = Blocks.front();
+
+  for (std::vector<BasicBlock*>::const_iterator i = Blocks.begin(), e = Blocks.end();
+       i != e; ++i) {
+    for (BasicBlock::succ_iterator Successor = succ_begin(*i), SEnd = succ_end(*i);
+        Successor != SEnd; ++Successor) {
+      if (header == *Successor)
+       ++numBackEdges;
+    }
+  }
+  return numBackEdges;
+}
+
 void Loop::print(std::ostream &OS) const {
   OS << std::string(getLoopDepth()*2, ' ') << "Loop Containing: ";
 
@@ -34,13 +57,14 @@ void Loop::print(std::ostream &OS) const {
   }
   OS << "\n";
 
-  std::copy(getSubLoops().begin(), getSubLoops().end(),
-            std::ostream_iterator<const Loop*>(OS, "\n"));
+  for (unsigned i = 0, e = getSubLoops().size(); i != e; ++i)
+    getSubLoops()[i]->print(OS);
 }
 
 //===----------------------------------------------------------------------===//
 // LoopInfo implementation
 //
+void LoopInfo::stub() {}
 
 bool LoopInfo::runOnFunction(Function &) {
   releaseMemory();
@@ -76,12 +100,12 @@ void LoopInfo::getAnalysisUsage(AnalysisUsage &AU) const {
 }
 
 void LoopInfo::print(std::ostream &OS) const {
-  std::copy(getTopLevelLoops().begin(), getTopLevelLoops().end(),
-            std::ostream_iterator<const Loop*>(OS, "\n"));
+  for (unsigned i = 0; i < TopLevelLoops.size(); ++i)
+    TopLevelLoops[i]->print(OS);
 }
 
 Loop *LoopInfo::ConsiderForLoop(BasicBlock *BB, const DominatorSet &DS) {
-  if (BBMap.find(BB) != BBMap.end()) return 0;   // Havn't processed this node?
+  if (BBMap.find(BB) != BBMap.end()) return 0;   // Haven't processed this node?
 
   std::vector<BasicBlock *> TodoStack;
 
@@ -128,3 +152,54 @@ Loop *LoopInfo::ConsiderForLoop(BasicBlock *BB, const DominatorSet &DS) {
 
   return L;
 }
+
+/// getLoopPreheader - If there is a preheader for this loop, return it.  A
+/// loop has a preheader if there is only one edge to the header of the loop
+/// from outside of the loop.  If this is the case, the block branching to the
+/// header of the loop is the preheader node.  The "preheaders" pass can be
+/// "Required" to ensure that there is always a preheader node for every loop.
+///
+/// This method returns null if there is no preheader for the loop (either
+/// because the loop is dead or because multiple blocks branch to the header
+/// node of this loop).
+///
+BasicBlock *Loop::getLoopPreheader() const {
+  // Keep track of nodes outside the loop branching to the header...
+  BasicBlock *Out = 0;
+
+  // Loop over the predecessors of the header node...
+  BasicBlock *Header = getHeader();
+  for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header);
+       PI != PE; ++PI)
+    if (!contains(*PI)) {     // If the block is not in the loop...
+      if (Out && Out != *PI)
+        return 0;             // Multiple predecessors outside the loop
+      Out = *PI;
+    }
+
+  // If there is exactly one preheader, return it.  If there was zero, then Out
+  // is still null.
+  return Out;
+}
+
+/// addBasicBlockToLoop - This function is used by other analyses to update loop
+/// information.  NewBB is set to be a new member of the current loop.  Because
+/// of this, it is added as a member of all parent loops, and is added to the
+/// specified LoopInfo object as being in the current basic block.  It is not
+/// valid to replace the loop header with this method.
+///
+void Loop::addBasicBlockToLoop(BasicBlock *NewBB, LoopInfo &LI) {
+  assert(LI[getHeader()] == this && "Incorrect LI specified for this loop!");
+  assert(NewBB && "Cannot add a null basic block to the loop!");
+  assert(LI[NewBB] == 0 && "BasicBlock already in the loop!");
+
+  // Add the loop mapping to the LoopInfo object...
+  LI.BBMap[NewBB] = this;
+
+  // Add the basic block to this loop and all parent loops...
+  Loop *L = this;
+  while (L) {
+    L->Blocks.push_back(NewBB);
+    L = L->getParentLoop();
+  }
+}