This huge changeset is a strictly cleanup change

Bugfixes will come in the next revision so that the diff is obvious.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2372 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 174 insertions, 228 deletions

diff --git a/lib/Transforms/Utils/PromoteMemoryToRegister.cpp b/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
index bbb131f..e9ca9f1 100644
--- a/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
+++ b/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
@@ -31,46 +31,44 @@ using namespace std;
 
 namespace {
 
-//instance of the promoter -- to keep all the local function data.
+// instance of the promoter -- to keep all the local function data.
 // gets re-created for each function processed
-class PromoteInstance
-{
-	protected:
-	vector<AllocaInst*>            		Allocas;   // the alloca instruction..
-	map<Instruction *, int>	   		AllocaLookup; //reverse mapping of above
-
-	vector<vector<BasicBlock *> >  		WriteSets; // index corresponds to Allocas
-	vector<vector<BasicBlock *> > 	 	PhiNodes;  // index corresponds to Allocas
-	vector<vector<Value *> > 		CurrentValue; //the current value stack
-
-	//list of instructions to remove at end of pass :)
-	vector<Instruction *> killlist;
-
-	set<BasicBlock *> 			visited;	//the basic blocks we've already visited
-	map<BasicBlock *, vector<PHINode *> > 	new_phinodes;	//the phinodes we're adding
-
-
-	void traverse(BasicBlock *f, BasicBlock * predecessor);
-	bool PromoteFunction(Function *F, DominanceFrontier &DF);
-	bool queuePhiNode(BasicBlock *bb, int alloca_index);
-	void findSafeAllocas(Function *M);
-	bool didchange;
-	public:
-	// I do this so that I can force the deconstruction of the local variables
-	PromoteInstance(Function *F, DominanceFrontier &DF)
-	{
-		didchange=PromoteFunction(F, DF);
-	}
-	//This returns whether the pass changes anything
-	operator bool () { return didchange; }
+class PromoteInstance {
+protected:
+  vector<AllocaInst*>          Allocas;      // the alloca instruction..
+  map<Instruction*, unsigned>  AllocaLookup; // reverse mapping of above
+  
+  vector<vector<BasicBlock*> > WriteSets;    // index corresponds to Allocas
+  vector<vector<BasicBlock*> > PhiNodes;     // index corresponds to Allocas
+  vector<vector<Value*> >      CurrentValue; // the current value stack
+  
+  //list of instructions to remove at end of pass :)
+  vector<Instruction *>        KillList;
+
+  set<BasicBlock*> visited;       // the basic blocks we've already visited
+  map<BasicBlock*, vector<PHINode*> > NewPhiNodes; // the phinodes we're adding
+
+  void traverse(BasicBlock *f, BasicBlock * predecessor);
+  bool PromoteFunction(Function *F, DominanceFrontier &DF);
+  bool QueuePhiNode(BasicBlock *bb, unsigned alloca_index);
+  void findSafeAllocas(Function *M);
+  bool didchange;
+public:
+  // I do this so that I can force the deconstruction of the local variables
+  PromoteInstance(Function *F, DominanceFrontier &DF) {
+    didchange = PromoteFunction(F, DF);
+  }
+  //This returns whether the pass changes anything
+  operator bool () { return didchange; }
 };
 
 }  // end of anonymous namespace
 
+
+
 // findSafeAllocas - Find allocas that are safe to promote
 //
-void PromoteInstance::findSafeAllocas(Function *F)  
-{
+void PromoteInstance::findSafeAllocas(Function *F) {
   BasicBlock *BB = F->getEntryNode();  // Get the entry node for the function
 
   // Look at all instructions in the entry node
@@ -84,224 +82,175 @@ void PromoteInstance::findSafeAllocas(Function *F)
 	  // Only allow nonindexed memory access instructions...
 	  if (MemAccessInst *MAI = dyn_cast<MemAccessInst>(*UI)) {
 	    if (MAI->hasIndices()) {  // indexed?
-	      // Allow the access if there is only one index and the index is zero.
+	      // Allow the access if there is only one index and the index is
+              // zero.
 	      if (*MAI->idx_begin() != ConstantUInt::get(Type::UIntTy, 0) ||
 		  MAI->idx_begin()+1 != MAI->idx_end()) {
-		isSafe = false; break;
+		isSafe = false;
+                break;
 	      }
 	    }
 	  } else {
 	    isSafe = false; break;   // Not a load or store?
 	  }
 	}
-	if (isSafe)              // If all checks pass, add alloca to safe list
-	  {
-	    AllocaLookup[AI]=Allocas.size();
-	    Allocas.push_back(AI);
-	  }
+	if (isSafe) {            // If all checks pass, add alloca to safe list
+          AllocaLookup[AI] = Allocas.size();
+          Allocas.push_back(AI);
+        }
       }
 }
 
 
 
-bool PromoteInstance::PromoteFunction(Function *F, DominanceFrontier & DF) {
-	// Calculate the set of safe allocas
-	findSafeAllocas(F);
-
-	// Add each alloca to the killlist
-	// note: killlist is destroyed MOST recently added to least recently.
-	killlist.assign(Allocas.begin(), Allocas.end());
+bool PromoteInstance::PromoteFunction(Function *F, DominanceFrontier &DF) {
+  // Calculate the set of safe allocas
+  findSafeAllocas(F);
+
+  // Add each alloca to the KillList.  Note: KillList is destroyed MOST recently
+  // added to least recently.
+  KillList.assign(Allocas.begin(), Allocas.end());
+
+  // Calculate the set of write-locations for each alloca.  This is analogous to
+  // counting the number of 'redefinitions' of each variable.
+  WriteSets.resize(Allocas.size());
+  for (unsigned i = 0; i != Allocas.size(); ++i) {
+    AllocaInst *AI = Allocas[i];
+    for (Value::use_iterator U =AI->use_begin(), E = AI->use_end(); U != E; ++U)
+      if (StoreInst *SI = dyn_cast<StoreInst>(*U))
+        // jot down the basic-block it came from
+        WriteSets[i].push_back(SI->getParent());
+  }
+
+  // Compute the locations where PhiNodes need to be inserted.  Look at the
+  // dominance frontier of EACH basic-block we have a write in
+  //
+  PhiNodes.resize(Allocas.size());
+  for (unsigned i = 0; i != Allocas.size(); ++i) {
+    for (unsigned j = 0; j != WriteSets[i].size(); j++) {
+      // Look up the DF for this write, add it to PhiNodes
+      DominanceFrontier::const_iterator it = DF.find(WriteSets[i][j]);
+      DominanceFrontier::DomSetType     S = it->second;
+      for (DominanceFrontier::DomSetType::iterator P = S.begin(), PE = S.end();
+           P != PE; ++P)
+        QueuePhiNode(*P, i);
+    }
+    
+    // Perform iterative step
+    for (unsigned k = 0; k != PhiNodes[i].size(); k++) {
+      DominanceFrontier::const_iterator it = DF.find(PhiNodes[i][k]);
+      DominanceFrontier::DomSetType     S = it->second;
+      for (DominanceFrontier::DomSetType::iterator P = S.begin(), PE = S.end();
+           P != PE; ++P)
+        QueuePhiNode(*P, i);
+    }
+  }
+
+  // Walks all basic blocks in the function performing the SSA rename algorithm
+  // and inserting the phi nodes we marked as necessary
+  //
+  CurrentValue.push_back(vector<Value *>(Allocas.size()));
+  traverse(F->front(), 0);  // there is no predecessor of the root node
+
+  // Remove all instructions marked by being placed in the KillList...
+  //
+  while (!KillList.empty()) {
+    Instruction *I = KillList.back();
+    KillList.pop_back();
+
+    //now go find..
+    I->getParent()->getInstList().remove(I);
+    delete I;
+  }
+
+  return !Allocas.empty();
+}
 
-	// Calculate the set of write-locations for each alloca.
-	// this is analogous to counting the number of 'redefinitions' of each variable.
-	for (unsigned i = 0; i<Allocas.size(); ++i)
-	{
-		AllocaInst * AI = Allocas[i];
-		WriteSets.push_back(std::vector<BasicBlock *>()); //add a new set
-		for (Value::use_iterator U = AI->use_begin();U!=AI->use_end();++U)
-		{
-			if (MemAccessInst *MAI = dyn_cast<StoreInst>(*U)) {
-				WriteSets[i].push_back(MAI->getParent()); // jot down the basic-block it came from
-			}
-		}
-	}
 
-	// Compute the locations where PhiNodes need to be inserted
-	// look at the dominance frontier of EACH basic-block we have a write in
-	PhiNodes.resize(Allocas.size());
-	for (unsigned i = 0; i<Allocas.size(); ++i)
-	{
-		for (unsigned j = 0; j<WriteSets[i].size(); j++)
-		{
-			//look up the DF for this write, add it to PhiNodes
-			DominanceFrontier::const_iterator it = DF.find(WriteSets[i][j]);
-			DominanceFrontier::DomSetType     s = (*it).second;
-			for (DominanceFrontier::DomSetType::iterator p = s.begin();p!=s.end(); ++p)
-			{
-				if (queuePhiNode(*p, i))
-                                  PhiNodes[i].push_back(*p);
-			}
-		}
-		// perform iterative step
-		for (unsigned k = 0; k<PhiNodes[i].size(); k++)
-		{
-			DominanceFrontier::const_iterator it = DF.find(PhiNodes[i][k]);
-			DominanceFrontier::DomSetType     s = it->second;
-			for (DominanceFrontier::DomSetType::iterator p = s.begin(); p!=s.end(); ++p)
-			{
-				if (queuePhiNode(*p,i))
-				PhiNodes[i].push_back(*p);
-			}
-		}
-	}
+// QueuePhiNode - queues a phi-node to be added to a basic-block for a specific
+// Alloca returns true if there wasn't already a phi-node for that variable
+//
+bool PromoteInstance::QueuePhiNode(BasicBlock *BB, unsigned i /*the alloca*/) {
+  // Look up the basic-block in question
+  vector<PHINode*> &BBPNs = NewPhiNodes[BB];
+  if (BBPNs.empty()) BBPNs.resize(Allocas.size());
 
-	// Walks all basic blocks in the function
-	// performing the SSA rename algorithm
-	// and inserting the phi nodes we marked as necessary
-	BasicBlock * f = F->front(); //get root basic-block
+  // If the BB already has a phi node added for the i'th alloca then we're done!
+  if (BBPNs[i]) return false;
 
-	CurrentValue.push_back(vector<Value *>(Allocas.size()));
+  // Create a phi-node using the dereferenced type...
+  PHINode *PN = new PHINode(Allocas[i]->getType()->getElementType(),
+                            Allocas[i]->getName()+".mem2reg");
+  BBPNs[i] = PN;
 
-	traverse(f, NULL);  // there is no predecessor of the root node
+  // Add the phi-node to the basic-block
+  BB->getInstList().push_front(PN);
 
+  PhiNodes[i].push_back(BB);
+  return true;
+}
 
-	// ** REMOVE EVERYTHING IN THE KILL-LIST **
-	// we need to kill 'uses' before root values
-	// so we should probably run through in reverse
-	for (vector<Instruction *>::reverse_iterator i = killlist.rbegin(); i!=killlist.rend(); ++i)
-	{
-		Instruction * r = *i;
-		BasicBlock * o = r->getParent();
-		//now go find..
+void PromoteInstance::traverse(BasicBlock *BB, BasicBlock *Pred) {
+  vector<Value *> &TOS = CurrentValue.back(); // look at top
 
-		BasicBlock::InstListType & l = o->getInstList();
-		o->getInstList().remove(r);
-		delete r;
-	}
+  // If this is a BB needing a phi node, lookup/create the phinode for each
+  // variable we need phinodes for.
+  vector<PHINode *> &BBPNs = NewPhiNodes[BB];
+  for (unsigned k = 0; k != BBPNs.size(); ++k)
+    if (BBPNs[k]) {
+      // at this point we can assume that the array has phi nodes.. let's add
+      // the incoming data
+      BBPNs[k]->addIncoming(TOS[k], Pred);
 
-	return !Allocas.empty();
-}
+      // also note that the active variable IS designated by the phi node
+      TOS[k] = BBPNs[k];
+    }
 
+  // don't revisit nodes
+  if (visited.count(BB)) return;
+  
+  // mark as visited
+  visited.insert(BB);
 
+  // keep track of the value of each variable we're watching.. how?
+  for (BasicBlock::iterator II = BB->begin(); II != BB->end(); ++II) {
+    Instruction *I = *II; //get the instruction
 
-void PromoteInstance::traverse(BasicBlock *f, BasicBlock * predecessor)
-{
-	vector<Value *> * tos = &CurrentValue.back(); //look at top-
-
-	//if this is a BB needing a phi node, lookup/create the phinode for
-	// each variable we need phinodes for.
-	map<BasicBlock *, vector<PHINode *> >::iterator nd = new_phinodes.find(f);
-	if (nd!=new_phinodes.end())
-	{
-		for (unsigned k = 0; k!=nd->second.size(); ++k)
-		if (nd->second[k])
-		{
-			//at this point we can assume that the array has phi nodes.. let's
-			// add the incoming data
-			if ((*tos)[k])
-			nd->second[k]->addIncoming((*tos)[k],predecessor);
-			//also note that the active variable IS designated by the phi node
-			(*tos)[k] = nd->second[k];
-		}
-	}
+    if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
+      Value *Ptr = LI->getPointerOperand();
 
-	//don't revisit nodes
-	if (visited.find(f)!=visited.end())
-	return;
-	//mark as visited
-	visited.insert(f);
-
-	BasicBlock::iterator i = f->begin();
-	//keep track of the value of each variable we're watching.. how?
-	while(i!=f->end())
-	{
-		Instruction * inst = *i; //get the instruction
-		//is this a write/read?
-		if (LoadInst * LI = dyn_cast<LoadInst>(inst))
-		{
-			// This is a bit weird...
-			Value * ptr = LI->getPointerOperand(); //of type value
-			if (AllocaInst * srcinstr = dyn_cast<AllocaInst>(ptr))
-			{
-				map<Instruction *, int>::iterator ai = AllocaLookup.find(srcinstr);
-				if (ai!=AllocaLookup.end())
-				{
-					if (Value *r = (*tos)[ai->second])
-					{
-						//walk the use list of this load and replace
-						// all uses with r
-						LI->replaceAllUsesWith(r);
-						//now delete the instruction.. somehow..
-						killlist.push_back((Instruction *)LI);
-					}
-				}
-			}
-		}
-		else if (StoreInst * SI = dyn_cast<StoreInst>(inst))
-		{
-			// delete this instruction and mark the name as the
-			// current holder of the value
-			Value * ptr =  SI->getPointerOperand(); //of type value
-			if (Instruction * srcinstr = dyn_cast<Instruction>(ptr))
-			{
-				map<Instruction *, int>::iterator ai = AllocaLookup.find(srcinstr);
-				if (ai!=AllocaLookup.end())
-				{
-					//what value were we writing?
-					Value * writeval = SI->getOperand(0);
-					//write down...
-					(*tos)[ai->second] = writeval;
-					//now delete it.. somehow?
-					killlist.push_back((Instruction *)SI);
-				}
-			}
-
-		}
-		else if (TerminatorInst * TI = dyn_cast<TerminatorInst>(inst))
-		{
-			// Recurse across our sucessors
-			for (unsigned i = 0; i!=TI->getNumSuccessors(); i++)
-			{
-				CurrentValue.push_back(CurrentValue.back());
-				traverse(TI->getSuccessor(i),f); //this node IS the predecessor
-				CurrentValue.pop_back();
-			}
-		}
-		i++;
-	}
-}
+      if (AllocaInst *Src = dyn_cast<AllocaInst>(Ptr)) {
+        map<Instruction*, unsigned>::iterator ai = AllocaLookup.find(Src);
+        if (ai != AllocaLookup.end()) {
+          Value *V = TOS[ai->second];
 
-// queues a phi-node to be added to a basic-block for a specific Alloca
-// returns true  if there wasn't already a phi-node for that variable
-
-
-bool PromoteInstance::queuePhiNode(BasicBlock *bb, int i /*the alloca*/)
-{
-	map<BasicBlock *, vector<PHINode *> >::iterator nd;
-	//look up the basic-block in question
-	nd = new_phinodes.find(bb);
-	//if the basic-block has no phi-nodes added, or at least none
-	//for the i'th alloca. then add.
-	if (nd==new_phinodes.end() || nd->second[i]==NULL)
-	{
-		//we're not added any phi nodes to this basicblock yet
-		// create the phi-node array.
-		if (nd==new_phinodes.end())
-		{
-			new_phinodes[bb] = vector<PHINode *>(Allocas.size());
-			nd = new_phinodes.find(bb);
-		}
-
-		//find the type the alloca returns
-		const PointerType * pt = Allocas[i]->getType();
-		//create a phi-node using the DEREFERENCED type
-		PHINode * ph = new PHINode(pt->getElementType(), Allocas[i]->getName()+".mem2reg");
-		nd->second[i] = ph;
-		//add the phi-node to the basic-block
-		bb->getInstList().push_front(ph);
-		return true;
-	}
-	return false;
+          // walk the use list of this load and replace all uses with r
+          LI->replaceAllUsesWith(V);
+          KillList.push_back(LI); // Mark the load to be deleted
+        }
+      }
+    } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
+      // delete this instruction and mark the name as the current holder of the
+      // value
+      Value *Ptr = SI->getPointerOperand();
+      if (AllocaInst *Dest = dyn_cast<AllocaInst>(Ptr)) {
+        map<Instruction *, unsigned>::iterator ai = AllocaLookup.find(Dest);
+        if (ai != AllocaLookup.end()) {
+          // what value were we writing?
+          TOS[ai->second] = SI->getOperand(0);
+          KillList.push_back(SI);  // Mark the store to be deleted
+        }
+      }
+      
+    } else if (TerminatorInst *TI = dyn_cast<TerminatorInst>(I)) {
+      // Recurse across our successors
+      for (unsigned i = 0; i != TI->getNumSuccessors(); i++) {
+        CurrentValue.push_back(CurrentValue.back());
+        traverse(TI->getSuccessor(i), BB); // This node becomes the predecessor
+        CurrentValue.pop_back();
+      }
+    }
+  }
 }
 
 
@@ -314,7 +263,6 @@ namespace {
     virtual bool runOnFunction(Function *F) {
       return (bool)PromoteInstance(F, getAnalysis<DominanceFrontier>());
     }
-    
 
     // getAnalysisUsage - We need dominance frontiers
     //
@@ -328,7 +276,5 @@ namespace {
 // createPromoteMemoryToRegister - Provide an entry point to create this pass.
 //
 Pass *createPromoteMemoryToRegister() {
-	return new PromotePass();
+  return new PromotePass();
 }
-
-