[llvm-commits] CVS: llvm/lib/Transforms/Scalar/GVNPRE.cpp
Owen Anderson
resistor at mac.com
Thu Jun 7 18:03:23 PDT 2007
Changes in directory llvm/lib/Transforms/Scalar:
GVNPRE.cpp updated: 1.22 -> 1.23
---
Log message:
Add partial redundancy elimination.
---
Diffs of the changes: (+249 -84)
GVNPRE.cpp | 333 +++++++++++++++++++++++++++++++++++++++++++++----------------
1 files changed, 249 insertions(+), 84 deletions(-)
Index: llvm/lib/Transforms/Scalar/GVNPRE.cpp
diff -u llvm/lib/Transforms/Scalar/GVNPRE.cpp:1.22 llvm/lib/Transforms/Scalar/GVNPRE.cpp:1.23
--- llvm/lib/Transforms/Scalar/GVNPRE.cpp:1.22 Tue Jun 5 20:27:49 2007
+++ llvm/lib/Transforms/Scalar/GVNPRE.cpp Thu Jun 7 20:03:01 2007
@@ -27,6 +27,7 @@
#include "llvm/Analysis/PostDominators.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/CFG.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include <algorithm>
@@ -64,6 +65,9 @@
private:
uint32_t nextValueNumber;
typedef std::map<Value*, uint32_t, ExprLT> ValueTable;
+ ValueTable VN;
+ std::set<Value*, ExprLT> MS;
+ std::set<Instruction*> createdExpressions;
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
@@ -73,25 +77,23 @@
// Helper fuctions
// FIXME: eliminate or document these better
- void dump(ValueTable& VN, std::set<Value*>& s);
- void dump_unique(ValueTable& VN, std::set<Value*, ExprLT>& s);
- void clean(ValueTable VN, std::set<Value*, ExprLT>& set);
- bool add(ValueTable& VN, std::set<Value*, ExprLT>& MS, Value* V);
- Value* find_leader(std::set<Value*, ExprLT>& vals, Value* v);
- Value* phi_translate(ValueTable& VN, std::set<Value*, ExprLT>& MS,
- std::set<Value*, ExprLT>& set,
+ void dump(std::set<Value*>& s);
+ void dump_unique(std::set<Value*, ExprLT>& s);
+ void clean(std::set<Value*, ExprLT>& set);
+ bool add(Value* V, uint32_t number);
+ Value* find_leader(std::set<Value*, ExprLT>& vals,
+ Value* v);
+ Value* phi_translate(std::set<Value*, ExprLT>& set,
Value* V, BasicBlock* pred);
- void phi_translate_set(ValueTable& VN, std::set<Value*, ExprLT>& MS,
- std::set<Value*, ExprLT>& anticIn, BasicBlock* B,
+ void phi_translate_set(std::set<Value*, ExprLT>& anticIn, BasicBlock* B,
std::set<Value*, ExprLT>& out);
- void topo_sort(ValueTable& VN, std::set<Value*, ExprLT>& set,
+ void topo_sort(std::set<Value*, ExprLT>& set,
std::vector<Value*>& vec);
// For a given block, calculate the generated expressions, temporaries,
// and the AVAIL_OUT set
- void CalculateAvailOut(ValueTable& VN, std::set<Value*, ExprLT>& MS,
- DomTreeNode* DI,
+ void CalculateAvailOut(DomTreeNode* DI,
std::set<Value*, ExprLT>& currExps,
std::set<PHINode*>& currPhis,
std::set<Value*>& currTemps,
@@ -111,35 +113,33 @@
-bool GVNPRE::add(ValueTable& VN, std::set<Value*, ExprLT>& MS, Value* V) {
- std::pair<ValueTable::iterator, bool> ret = VN.insert(std::make_pair(V, nextValueNumber));
- if (ret.second)
- nextValueNumber++;
+bool GVNPRE::add(Value* V, uint32_t number) {
+ std::pair<ValueTable::iterator, bool> ret = VN.insert(std::make_pair(V, number));
if (isa<BinaryOperator>(V) || isa<PHINode>(V))
MS.insert(V);
return ret.second;
}
-Value* GVNPRE::find_leader(std::set<Value*, ExprLT>& vals,
- Value* v) {
- ExprLT cmp;
+Value* GVNPRE::find_leader(std::set<Value*, ExprLT>& vals, Value* v) {
for (std::set<Value*, ExprLT>::iterator I = vals.begin(), E = vals.end();
- I != E; ++I)
- if (!cmp(v, *I) && !cmp(*I, v))
+ I != E; ++I) {
+ assert(VN.find(v) != VN.end() && "Value not numbered?");
+ assert(VN.find(*I) != VN.end() && "Value not numbered?");
+ if (VN[v] == VN[*I])
return *I;
+ }
return 0;
}
-Value* GVNPRE::phi_translate(ValueTable& VN, std::set<Value*, ExprLT>& MS,
- std::set<Value*, ExprLT>& set,
+Value* GVNPRE::phi_translate(std::set<Value*, ExprLT>& set,
Value* V, BasicBlock* pred) {
if (V == 0)
return 0;
if (BinaryOperator* BO = dyn_cast<BinaryOperator>(V)) {
Value* newOp1 = isa<Instruction>(BO->getOperand(0))
- ? phi_translate(VN, MS, set,
+ ? phi_translate(set,
find_leader(set, BO->getOperand(0)),
pred)
: BO->getOperand(0);
@@ -147,7 +147,7 @@
return 0;
Value* newOp2 = isa<Instruction>(BO->getOperand(1))
- ? phi_translate(VN, MS, set,
+ ? phi_translate(set,
find_leader(set, BO->getOperand(1)),
pred)
: BO->getOperand(1);
@@ -155,12 +155,14 @@
return 0;
if (newOp1 != BO->getOperand(0) || newOp2 != BO->getOperand(1)) {
- Value* newVal = BinaryOperator::create(BO->getOpcode(),
+ Instruction* newVal = BinaryOperator::create(BO->getOpcode(),
newOp1, newOp2,
BO->getName()+".gvnpre");
-
+ if (add(newVal, nextValueNumber))
+ nextValueNumber++;
if (!find_leader(set, newVal)) {
- add(VN, MS, newVal);
+ DOUT << "Creating value: " << std::hex << newVal << std::dec << "\n";
+ createdExpressions.insert(newVal);
return newVal;
} else {
delete newVal;
@@ -175,39 +177,42 @@
return V;
}
-void GVNPRE::phi_translate_set(GVNPRE::ValueTable& VN,
- std::set<Value*, ExprLT>& MS,
- std::set<Value*, ExprLT>& anticIn, BasicBlock* B,
+void GVNPRE::phi_translate_set(std::set<Value*, ExprLT>& anticIn, BasicBlock* B,
std::set<Value*, ExprLT>& out) {
for (std::set<Value*, ExprLT>::iterator I = anticIn.begin(),
E = anticIn.end(); I != E; ++I) {
- Value* V = phi_translate(VN, MS, anticIn, *I, B);
+ Value* V = phi_translate(anticIn, *I, B);
if (V != 0)
out.insert(V);
}
}
// Remove all expressions whose operands are not themselves in the set
-void GVNPRE::clean(GVNPRE::ValueTable VN, std::set<Value*, ExprLT>& set) {
+void GVNPRE::clean(std::set<Value*, ExprLT>& set) {
std::vector<Value*> worklist;
- topo_sort(VN, set, worklist);
+ topo_sort(set, worklist);
- while (!worklist.empty()) {
- Value* v = worklist.back();
- worklist.pop_back();
+ for (unsigned i = 0; i < worklist.size(); ++i) {
+ Value* v = worklist[i];
if (BinaryOperator* BO = dyn_cast<BinaryOperator>(v)) {
- bool lhsValid = false;
- for (std::set<Value*, ExprLT>::iterator I = set.begin(), E = set.end();
- I != E; ++I)
- if (VN[*I] == VN[BO->getOperand(0)]);
- lhsValid = true;
+ bool lhsValid = !isa<Instruction>(BO->getOperand(0));
+ if (!lhsValid)
+ for (std::set<Value*, ExprLT>::iterator I = set.begin(), E = set.end();
+ I != E; ++I)
+ if (VN[*I] == VN[BO->getOperand(0)]) {
+ lhsValid = true;
+ break;
+ }
- bool rhsValid = false;
+ bool rhsValid = !isa<Instruction>(BO->getOperand(1));
+ if (!rhsValid)
for (std::set<Value*, ExprLT>::iterator I = set.begin(), E = set.end();
I != E; ++I)
- if (VN[*I] == VN[BO->getOperand(1)]);
+ if (VN[*I] == VN[BO->getOperand(1)]) {
rhsValid = true;
+ break;
+ }
if (!lhsValid || !rhsValid)
set.erase(BO);
@@ -215,25 +220,26 @@
}
}
-void GVNPRE::topo_sort(GVNPRE::ValueTable& VN,
- std::set<Value*, ExprLT>& set,
+void GVNPRE::topo_sort(std::set<Value*, ExprLT>& set,
std::vector<Value*>& vec) {
- std::set<Value*, ExprLT> toErase;
+ std::set<Value*, ExprLT> toErase;
for (std::set<Value*, ExprLT>::iterator I = set.begin(), E = set.end();
I != E; ++I) {
if (BinaryOperator* BO = dyn_cast<BinaryOperator>(*I))
for (std::set<Value*, ExprLT>::iterator SI = set.begin(); SI != E; ++SI) {
- if (VN[BO->getOperand(0)] == VN[*SI] || VN[BO->getOperand(1)] == VN[*SI]) {
- toErase.insert(BO);
+ if (VN[BO->getOperand(0)] == VN[*SI] ||
+ VN[BO->getOperand(1)] == VN[*SI]) {
+ toErase.insert(*SI);
}
}
}
std::vector<Value*> Q;
- std::insert_iterator<std::vector<Value*> > q_ins(Q, Q.begin());
- std::set_difference(set.begin(), set.end(),
- toErase.begin(), toErase.end(),
- q_ins);
+ for (std::set<Value*, ExprLT>::iterator I = set.begin(), E = set.end();
+ I != E; ++I) {
+ if (toErase.find(*I) == toErase.end())
+ Q.push_back(*I);
+ }
std::set<Value*> visited;
while (!Q.empty()) {
@@ -263,7 +269,7 @@
}
-void GVNPRE::dump(GVNPRE::ValueTable& VN, std::set<Value*>& s) {
+void GVNPRE::dump(std::set<Value*>& s) {
DOUT << "{ ";
for (std::set<Value*>::iterator I = s.begin(), E = s.end();
I != E; ++I) {
@@ -272,7 +278,7 @@
DOUT << "}\n\n";
}
-void GVNPRE::dump_unique(GVNPRE::ValueTable& VN, std::set<Value*, ExprLT>& s) {
+void GVNPRE::dump_unique(std::set<Value*, ExprLT>& s) {
DOUT << "{ ";
for (std::set<Value*>::iterator I = s.begin(), E = s.end();
I != E; ++I) {
@@ -281,8 +287,7 @@
DOUT << "}\n\n";
}
-void GVNPRE::CalculateAvailOut(GVNPRE::ValueTable& VN, std::set<Value*, ExprLT>& MS,
- DomTreeNode* DI,
+void GVNPRE::CalculateAvailOut(DomTreeNode* DI,
std::set<Value*, ExprLT>& currExps,
std::set<PHINode*>& currPhis,
std::set<Value*>& currTemps,
@@ -302,7 +307,8 @@
// Handle PHI nodes...
if (PHINode* p = dyn_cast<PHINode>(BI)) {
- add(VN, MS, p);
+ if (add(p, nextValueNumber))
+ nextValueNumber++;
currPhis.insert(p);
// Handle binary ops...
@@ -310,7 +316,8 @@
Value* leftValue = BO->getOperand(0);
Value* rightValue = BO->getOperand(1);
- add(VN, MS, BO);
+ if (add(BO, nextValueNumber))
+ nextValueNumber++;
if (isa<Instruction>(leftValue))
currExps.insert(leftValue);
@@ -320,7 +327,8 @@
// Handle unsupported ops
} else if (!BI->isTerminator()){
- add(VN, MS, BI);
+ if (add(BI, nextValueNumber))
+ nextValueNumber++;
currTemps.insert(BI);
}
@@ -330,8 +338,9 @@
}
bool GVNPRE::runOnFunction(Function &F) {
- ValueTable VN;
- std::set<Value*, ExprLT> maximalSet;
+ VN.clear();
+ MS.clear();
+ createdExpressions.clear();
std::map<BasicBlock*, std::set<Value*, ExprLT> > generatedExpressions;
std::map<BasicBlock*, std::set<PHINode*> > generatedPhis;
@@ -355,12 +364,12 @@
std::set<Value*>& currTemps = generatedTemporaries[DI->getBlock()];
std::set<Value*, ExprLT>& currAvail = availableOut[DI->getBlock()];
- CalculateAvailOut(VN, maximalSet, *DI, currExps, currPhis,
+ CalculateAvailOut(*DI, currExps, currPhis,
currTemps, currAvail, availableOut);
}
DOUT << "Maximal Set: ";
- dump_unique(VN, maximalSet);
+ dump_unique(MS);
DOUT << "\n";
PostDominatorTree &PDT = getAnalysis<PostDominatorTree>();
@@ -377,16 +386,16 @@
// Top-down walk of the postdominator tree
for (df_iterator<DomTreeNode*> PDI =
- df_begin(PDT.getRootNode()), E = df_end(DT.getRootNode());
+ df_begin(PDT.getRootNode()), E = df_end(PDT.getRootNode());
PDI != E; ++PDI) {
BasicBlock* BB = PDI->getBlock();
DOUT << "Block: " << BB->getName() << "\n";
DOUT << "TMP_GEN: ";
- dump(VN, generatedTemporaries[BB]);
+ dump(generatedTemporaries[BB]);
DOUT << "\n";
DOUT << "EXP_GEN: ";
- dump_unique(VN, generatedExpressions[BB]);
+ dump_unique(generatedExpressions[BB]);
visited.insert(BB);
std::set<Value*, ExprLT>& anticIn = anticipatedIn[BB];
@@ -395,9 +404,9 @@
if (BB->getTerminator()->getNumSuccessors() == 1) {
if (visited.find(BB->getTerminator()->getSuccessor(0)) ==
visited.end())
- phi_translate_set(VN, maximalSet, maximalSet, BB, anticOut);
+ phi_translate_set(MS, BB, anticOut);
else
- phi_translate_set(VN, maximalSet,
+ phi_translate_set(
anticipatedIn[BB->getTerminator()->getSuccessor(0)], BB, anticOut);
} else if (BB->getTerminator()->getNumSuccessors() > 1) {
BasicBlock* first = BB->getTerminator()->getSuccessor(0);
@@ -420,7 +429,7 @@
}
DOUT << "ANTIC_OUT: ";
- dump_unique(VN, anticOut);
+ dump_unique(anticOut);
DOUT << "\n";
std::set<Value*, ExprLT> S;
@@ -438,10 +447,10 @@
anticIn.insert(*I);
}
- clean(VN, anticIn);
+ clean(anticIn);
DOUT << "ANTIC_IN: ";
- dump_unique(VN, anticIn);
+ dump_unique(anticIn);
DOUT << "\n";
if (old.size() != anticIn.size())
@@ -459,25 +468,173 @@
DOUT << "Name: " << I->getName().c_str() << "\n";
DOUT << "TMP_GEN: ";
- dump(VN, generatedTemporaries[I]);
+ dump(generatedTemporaries[I]);
DOUT << "\n";
DOUT << "EXP_GEN: ";
- dump_unique(VN, generatedExpressions[I]);
+ dump_unique(generatedExpressions[I]);
DOUT << "\n";
DOUT << "ANTIC_IN: ";
- dump_unique(VN, anticipatedIn[I]);
+ dump_unique(anticipatedIn[I]);
DOUT << "\n";
DOUT << "AVAIL_OUT: ";
- dump_unique(VN, availableOut[I]);
+ dump_unique(availableOut[I]);
DOUT << "\n";
}
// Phase 2: Insert
- // FIXME: Not implemented yet
+
+ DOUT<< "\nPhase 2: Insertion\n";
+
+ std::map<BasicBlock*, std::set<Value*, ExprLT> > new_sets;
+ unsigned i_iterations = 0;
+ bool new_stuff = true;
+ while (new_stuff) {
+ new_stuff = false;
+ DOUT << "Iteration: " << i_iterations << "\n\n";
+ for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
+ E = df_end(DT.getRootNode()); DI != E; ++DI) {
+ BasicBlock* BB = DI->getBlock();
+
+ std::set<Value*, ExprLT>& new_set = new_sets[BB];
+ std::set<Value*, ExprLT>& availOut = availableOut[BB];
+ std::set<Value*, ExprLT>& anticIn = anticipatedIn[BB];
+
+ // Replace leaders with leaders inherited from dominator
+ if (DI->getIDom() != 0) {
+ std::set<Value*, ExprLT>& dom_set = new_sets[DI->getIDom()->getBlock()];
+ for (std::set<Value*, ExprLT>::iterator I = dom_set.begin(),
+ E = dom_set.end(); I != E; ++I) {
+ new_set.insert(*I);
+
+ std::set<Value*, ExprLT>::iterator val = availOut.find(*I);
+ if (val != availOut.end())
+ new_set.erase(val);
+ new_set.insert(*I);
+ }
+ }
+
+ // If there is more than one predecessor...
+ if (pred_begin(BB) != pred_end(BB) && ++pred_begin(BB) != pred_end(BB)) {
+ std::vector<Value*> workList;
+ topo_sort(anticIn, workList);
+
+ DOUT << "Merge Block: " << BB->getName() << "\n";
+ DOUT << "ANTIC_IN: ";
+ dump_unique(anticIn);
+ DOUT << "\n";
+
+ while (!workList.empty()) {
+ Value* e = workList.back();
+ workList.pop_back();
+
+ if (isa<BinaryOperator>(e)) {
+ if (find_leader(availableOut[DI->getIDom()->getBlock()], e) != 0)
+ continue;
+
+ std::map<BasicBlock*, Value*> avail;
+ bool by_some = false;
+ int num_avail = 0;
+
+ for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE;
+ ++PI) {
+ Value *e2 = phi_translate(anticIn, e, *PI);
+ Value *e3 = find_leader(availableOut[*PI], e2);
+
+ if (e3 == 0) {
+ std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
+ if (av != avail.end())
+ avail.erase(av);
+ avail.insert(std::make_pair(*PI, e2));
+ } else {
+ std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
+ if (av != avail.end())
+ avail.erase(av);
+ avail.insert(std::make_pair(*PI, e3));
+
+ by_some = true;
+ num_avail++;
+ }
+ }
+
+ if (by_some &&
+ num_avail < std::distance(pred_begin(BB), pred_end(BB))) {
+ DOUT << "Processing Value: ";
+ DEBUG(e->dump());
+ DOUT << "\n\n";
+
+ for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
+ PI != PE; ++PI) {
+ Value* e2 = avail[*PI];
+ if (!find_leader(availableOut[*PI], e2)) {
+ BinaryOperator* BO = cast<BinaryOperator>(e2);
+
+ Value* s1 = 0;
+ if (isa<Instruction>(BO->getOperand(0)))
+ s1 = find_leader(availableOut[*PI], BO->getOperand(0));
+ else
+ s1 = BO->getOperand(0);
+
+ Value* s2 = 0;
+ if (isa<Instruction>(BO->getOperand(1)))
+ s2 = find_leader(availableOut[*PI], BO->getOperand(1));
+ else
+ s2 = BO->getOperand(1);
+
+ Value* newVal = BinaryOperator::create(BO->getOpcode(),
+ s1, s2,
+ BO->getName()+".gvnpre",
+ (*PI)->getTerminator());
+ add(newVal, VN[BO]);
+ availableOut[*PI].insert(newVal);
+
+ DOUT << "Creating value: " << std::hex << newVal << std::dec << "\n";
+
+ std::map<BasicBlock*, Value*>::iterator av = avail.find(*PI);
+ if (av != avail.end())
+ avail.erase(av);
+ avail.insert(std::make_pair(*PI, newVal));
+ }
+ }
+
+ PHINode* p = 0;
+
+ for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
+ PI != PE; ++PI) {
+ if (p == 0)
+ p = new PHINode(avail[*PI]->getType(), "gvnpre-join",
+ BB->begin());
+
+ p->addIncoming(avail[*PI], *PI);
+ }
+
+ add(p, VN[e]);
+ DOUT << "Creating value: " << std::hex << p << std::dec << "\n";
+
+ availOut.insert(p);
+ new_stuff = true;
+
+ DOUT << "Preds After Processing: ";
+ for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
+ PI != PE; ++PI)
+ DEBUG((*PI)->dump());
+ DOUT << "\n\n";
+
+ DOUT << "Merge Block After Processing: ";
+ DEBUG(BB->dump());
+ DOUT << "\n\n";
+
+ new_set.insert(p);
+ }
+ }
+ }
+ }
+ }
+ i_iterations++;
+ }
// Phase 3: Eliminate
for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
@@ -488,13 +645,15 @@
for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
BI != BE; ++BI) {
- Value* leader = find_leader(availableOut[BB], BI);
- if (leader != 0)
- if (Instruction* Instr = dyn_cast<Instruction>(leader))
- if (Instr->getParent() != 0 && Instr != BI) {
- BI->replaceAllUsesWith(leader);
- erase.push_back(BI);
- }
+ if (!BI->isTerminator()) {
+ Value* leader = find_leader(availableOut[BB], BI);
+ if (leader != 0)
+ if (Instruction* Instr = dyn_cast<Instruction>(leader))
+ if (Instr->getParent() != 0 && Instr != BI) {
+ BI->replaceAllUsesWith(leader);
+ erase.push_back(BI);
+ }
+ }
}
for (std::vector<Instruction*>::iterator I = erase.begin(), E = erase.end();
@@ -502,5 +661,11 @@
(*I)->eraseFromParent();
}
+ // Phase 4: Cleanup
+ for (std::set<Instruction*>::iterator I = createdExpressions.begin(),
+ E = createdExpressions.end(); I != E; ++I) {
+ delete *I;
+ }
+
return false;
}
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