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Clean up ADCE by removing extraneous wrapper class

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llvm-svn: 2494
This commit is contained in:
Chris Lattner 2002-05-06 17:27:57 +00:00
parent c5279917bc
commit b40c1bf6f7
1 changed files with 42 additions and 43 deletions
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85
lib/Transforms/Scalar/ADCE.cpp
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@ -21,14 +21,16 @@ using std::cerr;
#define DEBUG_ADCE 1
namespace {
//===----------------------------------------------------------------------===//
// ADCE Class
//
// This class does all of the work of Agressive Dead Code Elimination.
// It's public interface consists of a constructor and a doADCE() method.
//
class ADCE {
Function *M; // The function that we are working on
class ADCE : public FunctionPass {
Function *Func; // The function that we are working on
std::vector<Instruction*> WorkList; // Instructions that just became live
std::set<Instruction*> LiveSet; // The set of live instructions
bool MadeChanges;
@ -37,17 +39,33 @@ class ADCE {
// The public interface for this class
//
public:
// ADCE Ctor - Save the function to operate on...
inline ADCE(Function *f) : M(f), MadeChanges(false) {}
const char *getPassName() const { return "Aggressive Dead Code Elimination"; }
// doADCE - Execute the Agressive Dead Code Elimination Algorithm
//
virtual bool runOnFunction(Function *F) {
Func = F; MadeChanges = false;
doADCE(getAnalysis<DominanceFrontier>(DominanceFrontier::PostDomID));
assert(WorkList.empty());
LiveSet.clear();
return MadeChanges;
}
// getAnalysisUsage - We require post dominance frontiers (aka Control
// Dependence Graph)
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired(DominanceFrontier::PostDomID);
}
// doADCE() - Run the Agressive Dead Code Elimination algorithm, returning
// true if the function was modified.
bool doADCE(DominanceFrontier &CDG);
//===--------------------------------------------------------------------===//
// The implementation of this class
//
private:
// doADCE() - Run the Agressive Dead Code Elimination algorithm, returning
// true if the function was modified.
//
void doADCE(DominanceFrontier &CDG);
inline void markInstructionLive(Instruction *I) {
if (LiveSet.count(I)) return;
#ifdef DEBUG_ADCE
@ -71,14 +89,19 @@ private:
const std::set<BasicBlock*> &AliveBlocks);
};
} // End of anonymous namespace
Pass *createAgressiveDCEPass() {
return new ADCE();
}
// doADCE() - Run the Agressive Dead Code Elimination algorithm, returning
// true if the function was modified.
//
bool ADCE::doADCE(DominanceFrontier &CDG) {
void ADCE::doADCE(DominanceFrontier &CDG) {
#ifdef DEBUG_ADCE
cerr << "Function: " << M;
cerr << "Function: " << Func;
#endif
// Iterate over all of the instructions in the function, eliminating trivially
@ -87,8 +110,7 @@ bool ADCE::doADCE(DominanceFrontier &CDG) {
// instructions live in basic blocks that are unreachable. These blocks will
// be eliminated later, along with the instructions inside.
//
for (df_iterator<Function*> BBI = df_begin(M),
BBE = df_end(M);
for (df_iterator<Function*> BBI = df_begin(Func), BBE = df_end(Func);
BBI != BBE; ++BBI) {
BasicBlock *BB = *BBI;
for (BasicBlock::iterator II = BB->begin(), EI = BB->end(); II != EI; ) {
@ -156,7 +178,7 @@ bool ADCE::doADCE(DominanceFrontier &CDG) {
#ifdef DEBUG_ADCE
cerr << "Current Function: X = Live\n";
for (Function::iterator I = M->begin(), E = M->end(); I != E; ++I)
for (Function::iterator I = Func->begin(), E = Func->end(); I != E; ++I)
for (BasicBlock::iterator BI = (*I)->begin(), BE = (*I)->end();
BI != BE; ++BI) {
if (LiveSet.count(*BI)) cerr << "X ";
@ -168,14 +190,14 @@ bool ADCE::doADCE(DominanceFrontier &CDG) {
// order, patching up references to dead blocks...
//
std::set<BasicBlock*> VisitedBlocks;
BasicBlock *EntryBlock = fixupCFG(M->front(), VisitedBlocks, AliveBlocks);
if (EntryBlock && EntryBlock != M->front()) {
BasicBlock *EntryBlock = fixupCFG(Func->front(), VisitedBlocks, AliveBlocks);
if (EntryBlock && EntryBlock != Func->front()) {
if (isa<PHINode>(EntryBlock->front())) {
// Cannot make the first block be a block with a PHI node in it! Instead,
// strip the first basic block of the function to contain no instructions,
// then add a simple branch to the "real" entry node...
//
BasicBlock *E = M->front();
BasicBlock *E = Func->front();
if (!isa<TerminatorInst>(E->front()) || // Check for an actual change...
cast<TerminatorInst>(E->front())->getNumSuccessors() != 1 ||
cast<TerminatorInst>(E->front())->getSuccessor(0) != EntryBlock) {
@ -191,8 +213,8 @@ bool ADCE::doADCE(DominanceFrontier &CDG) {
} else {
// We need to move the new entry block to be the first bb of the function
Function::iterator EBI = find(M->begin(), M->end(), EntryBlock);
std::swap(*EBI, *M->begin()); // Exchange old location with start of fn
Function::iterator EBI = find(Func->begin(), Func->end(), EntryBlock);
std::swap(*EBI, *Func->begin()); // Exchange old location with start of fn
MadeChanges = true;
}
}
@ -200,7 +222,7 @@ bool ADCE::doADCE(DominanceFrontier &CDG) {
// Now go through and tell dead blocks to drop all of their references so they
// can be safely deleted.
//
for (Function::iterator BI = M->begin(), BE = M->end(); BI != BE; ++BI) {
for (Function::iterator BI = Func->begin(), BE = Func->end(); BI != BE; ++BI){
BasicBlock *BB = *BI;
if (!AliveBlocks.count(BB)) {
BB->dropAllReferences();
@ -211,16 +233,14 @@ bool ADCE::doADCE(DominanceFrontier &CDG) {
// now because we know that there are no references to dead blocks (because
// they have dropped all of their references...
//
for (Function::iterator BI = M->begin(); BI != M->end();) {
for (Function::iterator BI = Func->begin(); BI != Func->end();) {
if (!AliveBlocks.count(*BI)) {
delete M->getBasicBlocks().remove(BI);
delete Func->getBasicBlocks().remove(BI);
MadeChanges = true;
continue; // Don't increment iterator
}
++BI; // Increment iterator...
}
return MadeChanges;
}
@ -287,24 +307,3 @@ BasicBlock *ADCE::fixupCFG(BasicBlock *BB, std::set<BasicBlock*> &VisitedBlocks,
}
}
namespace {
struct AgressiveDCE : public FunctionPass {
const char *getPassName() const {return "Aggressive Dead Code Elimination";}
// doADCE - Execute the Agressive Dead Code Elimination Algorithm
//
virtual bool runOnFunction(Function *F) {
return ADCE(F).doADCE(
getAnalysis<DominanceFrontier>(DominanceFrontier::PostDomID));
}
// getAnalysisUsage - We require post dominance frontiers (aka Control
// Dependence Graph)
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired(DominanceFrontier::PostDomID);
}
};
}
Pass *createAgressiveDCEPass() {
return new AgressiveDCE();
}