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DomForest is a forest of registers, not instructions.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43754 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2007-11-06 05:22:43 +00:00
parent a1cd224a23
commit ee49b5385b
1 changed files with 47 additions and 25 deletions
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72
lib/CodeGen/StrongPHIElimination.cpp
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@ -59,14 +59,14 @@ namespace {
struct DomForestNode {
private:
std::vector<DomForestNode*> children;
MachineInstr* instr;
unsigned reg;
void addChild(DomForestNode* DFN) { children.push_back(DFN); }
public:
typedef std::vector<DomForestNode*>::iterator iterator;
DomForestNode(MachineInstr* MI, DomForestNode* parent) : instr(MI) {
DomForestNode(unsigned r, DomForestNode* parent) : reg(r) {
if (parent)
parent->addChild(this);
}
@ -76,7 +76,7 @@ namespace {
delete *I;
}
inline MachineInstr* getInstr() { return instr; }
inline unsigned getReg() { return reg; }
inline DomForestNode::iterator begin() { return children.begin(); }
inline DomForestNode::iterator end() { return children.end(); }
@ -89,9 +89,9 @@ namespace {
void computeDFS(MachineFunction& MF);
void processPHI(MachineInstr* P);
std::vector<DomForestNode*>
computeDomForest(SmallPtrSet<MachineInstr*, 8>& instrs);
std::vector<DomForestNode*> computeDomForest(std::set<unsigned>& instrs);
};
@ -149,51 +149,60 @@ void StrongPHIElimination::computeDFS(MachineFunction& MF) {
class PreorderSorter {
private:
DenseMap<MachineBasicBlock*, unsigned>& preorder;
LiveVariables& LV;
public:
PreorderSorter(DenseMap<MachineBasicBlock*, unsigned>& p) : preorder(p) { }
PreorderSorter(DenseMap<MachineBasicBlock*, unsigned>& p,
LiveVariables& L) : preorder(p), LV(L) { }
bool operator()(MachineInstr* A, MachineInstr* B) {
bool operator()(unsigned A, unsigned B) {
if (A == B)
return false;
if (preorder[A->getParent()] < preorder[B->getParent()])
MachineBasicBlock* ABlock = LV.getVarInfo(A).DefInst->getParent();
MachineBasicBlock* BBlock = LV.getVarInfo(A).DefInst->getParent();
if (preorder[ABlock] < preorder[BBlock])
return true;
else if (preorder[A->getParent()] > preorder[B->getParent()])
else if (preorder[ABlock] > preorder[BBlock])
return false;
if (A->getOpcode() == TargetInstrInfo::PHI &&
B->getOpcode() == TargetInstrInfo::PHI)
return A < B;
MachineInstr* begin = A->getParent()->begin();
return std::distance(begin, A) < std::distance(begin, B);
assert(0 && "Error sorting by dominance!");
return false;
}
};
std::vector<StrongPHIElimination::DomForestNode*>
StrongPHIElimination::computeDomForest(SmallPtrSet<MachineInstr*, 8>& instrs) {
StrongPHIElimination::computeDomForest(std::set<unsigned>& regs) {
LiveVariables& LV = getAnalysis<LiveVariables>();
DomForestNode* VirtualRoot = new DomForestNode(0, 0);
maxpreorder.insert(std::make_pair((MachineBasicBlock*)0, ~0UL));
std::vector<MachineInstr*> worklist;
worklist.reserve(instrs.size());
for (SmallPtrSet<MachineInstr*, 8>::iterator I = instrs.begin(),
E = instrs.end(); I != E; ++I)
std::vector<unsigned> worklist;
worklist.reserve(regs.size());
for (std::set<unsigned>::iterator I = regs.begin(), E = regs.end();
I != E; ++I)
worklist.push_back(*I);
PreorderSorter PS(preorder);
PreorderSorter PS(preorder, LV);
std::sort(worklist.begin(), worklist.end(), PS);
DomForestNode* CurrentParent = VirtualRoot;
std::vector<DomForestNode*> stack;
stack.push_back(VirtualRoot);
for (std::vector<MachineInstr*>::iterator I = worklist.begin(),
E = worklist.end(); I != E; ++I) {
while (preorder[(*I)->getParent()] >
maxpreorder[CurrentParent->getInstr()->getParent()]) {
for (std::vector<unsigned>::iterator I = worklist.begin(), E = worklist.end();
I != E; ++I) {
unsigned pre = preorder[LV.getVarInfo(*I).DefInst->getParent()];
MachineBasicBlock* parentBlock =
LV.getVarInfo(CurrentParent->getReg()).DefInst->getParent();
while (pre > maxpreorder[parentBlock]) {
stack.pop_back();
CurrentParent = stack.back();
parentBlock = LV.getVarInfo(CurrentParent->getReg()).DefInst->getParent();
}
DomForestNode* child = new DomForestNode(*I, CurrentParent);
@ -206,9 +215,22 @@ StrongPHIElimination::computeDomForest(SmallPtrSet<MachineInstr*, 8>& instrs) {
return ret;
}
void StrongPHIElimination::processPHI(MachineInstr* P) {
}
bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
computeDFS(Fn);
for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) {
for (MachineBasicBlock::iterator BI = I->begin(), BE = I->end(); BI != BE;
++BI) {
if (BI->getOpcode() == TargetInstrInfo::PHI)
processPHI(BI);
else
break;
}
}
return false;
}