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This huge changeset is a strictly cleanup change

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

llvm-svn: 2372
This commit is contained in:
Chris Lattner 2002-04-28 18:27:55 +00:00
parent d17fdd5494
commit 246083577b
1 changed files with 167 additions and 221 deletions
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388
lib/Transforms/Utils/PromoteMemoryToRegister.cpp
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@ -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
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;
vector<vector<BasicBlock *> > WriteSets; // index corresponds to Allocas
vector<vector<BasicBlock *> > PhiNodes; // index corresponds to Allocas
vector<vector<Value *> > CurrentValue; //the current value stack
set<BasicBlock*> visited; // the basic blocks we've already visited
map<BasicBlock*, vector<PHINode*> > NewPhiNodes; // the phinodes we're adding
//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; }
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);
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());
// 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.
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
}
}
}
// 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();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);
}
}
}
// 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
BasicBlock * f = F->front(); //get root basic-block
// 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
CurrentValue.push_back(vector<Value *>(Allocas.size()));
// Remove all instructions marked by being placed in the KillList...
//
while (!KillList.empty()) {
Instruction *I = KillList.back();
KillList.pop_back();
traverse(f, NULL); // there is no predecessor of the root node
//now go find..
I->getParent()->getInstList().remove(I);
delete I;
}
// ** 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..
BasicBlock::InstListType & l = o->getInstList();
o->getInstList().remove(r);
delete r;
}
return !Allocas.empty();
return !Allocas.empty();
}
// 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());
void PromoteInstance::traverse(BasicBlock *f, BasicBlock * predecessor)
{
vector<Value *> * tos = &CurrentValue.back(); //look at top-
// If the BB already has a phi node added for the i'th alloca then we're done!
if (BBPNs[i]) return false;
//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];
}
}
// Create a phi-node using the dereferenced type...
PHINode *PN = new PHINode(Allocas[i]->getType()->getElementType(),
Allocas[i]->getName()+".mem2reg");
BBPNs[i] = PN;
//don't revisit nodes
if (visited.find(f)!=visited.end())
return;
//mark as visited
visited.insert(f);
// Add the phi-node to the basic-block
BB->getInstList().push_front(PN);
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++;
}
PhiNodes[i].push_back(BB);
return true;
}
// 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
void PromoteInstance::traverse(BasicBlock *BB, BasicBlock *Pred) {
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.
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);
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);
}
// also note that the active variable IS designated by the phi node
TOS[k] = BBPNs[k];
}
//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;
// 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
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
Value *Ptr = LI->getPointerOperand();
if (AllocaInst *Src = dyn_cast<AllocaInst>(Ptr)) {
map<Instruction*, unsigned>::iterator ai = AllocaLookup.find(Src);
if (ai != AllocaLookup.end()) {
Value *V = TOS[ai->second];
// 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();
}