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Significantly clean up SCCP pass. Now the two classes are merged and in

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an anonymous namespace where they belong.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2415 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2002-04-29 21:26:08 +00:00
parent f737121054
commit 0dbfc05a2a
1 changed files with 38 additions and 45 deletions
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83
lib/Transforms/Scalar/SCCP.cpp
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@ -33,6 +33,7 @@ using std::cerr;
// InstVal class - This class represents the different lattice values that an
// instruction may occupy. It is a simple class with value semantics.
//
namespace {
class InstVal {
enum {
undefined, // This instruction has no known value
@ -72,34 +73,37 @@ public:
inline Constant *getConstant() const { return ConstantVal; }
};
} // end anonymous namespace
//===----------------------------------------------------------------------===//
// SCCP Class
//
// This class does all of the work of Sparse Conditional Constant Propogation.
// It's public interface consists of a constructor and a doSCCP() function.
//
class SCCP : public InstVisitor<SCCP> {
Function *M; // The function that we are working on
namespace {
class SCCP : public FunctionPass, public InstVisitor<SCCP> {
std::set<BasicBlock*> BBExecutable;// The basic blocks that are executable
std::map<Value*, InstVal> ValueState; // The state each value is in...
std::vector<Instruction*> InstWorkList;// The instruction work list
std::vector<BasicBlock*> BBWorkList; // The BasicBlock work list
//===--------------------------------------------------------------------===//
// The public interface for this class
//
public:
// SCCP Ctor - Save the function to operate on...
inline SCCP(Function *f) : M(f) {}
const char *getPassName() const {
return "Sparse Conditional Constant Propogation";
}
// runOnFunction - Run the Sparse Conditional Constant Propogation algorithm,
// and return true if the function was modified.
//
bool runOnFunction(Function *F);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
// FIXME: SCCP does not preserve the CFG because it folds terminators!
//AU.preservesCFG();
}
// doSCCP() - Run the Sparse Conditional Constant Propogation algorithm, and
// return true if the function was modified.
bool doSCCP();
//===--------------------------------------------------------------------===//
// The implementation of this class
@ -200,18 +204,27 @@ private:
//
void OperandChangedState(User *U);
};
} // end anonymous namespace
// createSCCPPass - This is the public interface to this file...
//
Pass *createSCCPPass() {
return new SCCP();
}
//===----------------------------------------------------------------------===//
// SCCP Class Implementation
// doSCCP() - Run the Sparse Conditional Constant Propogation algorithm, and
// return true if the function was modified.
// runOnFunction() - Run the Sparse Conditional Constant Propogation algorithm,
// and return true if the function was modified.
//
bool SCCP::doSCCP() {
bool SCCP::runOnFunction(Function *F) {
// Mark the first block of the function as being executable...
markExecutable(M->front());
markExecutable(F->front());
// Process the work lists until their are empty!
while (!BBWorkList.empty() || !InstWorkList.empty()) {
@ -252,7 +265,7 @@ bool SCCP::doSCCP() {
}
#if 0
for (Function::iterator BBI = M->begin(), BBEnd = M->end();
for (Function::iterator BBI = F->begin(), BBEnd = F->end();
BBI != BBEnd; ++BBI)
if (!BBExecutable.count(*BBI))
cerr << "BasicBlock Dead:" << *BBI;
@ -263,8 +276,8 @@ bool SCCP::doSCCP() {
// constants if we have found them to be of constant values.
//
bool MadeChanges = false;
for (Function::iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI) {
BasicBlock *BB = *MI;
for (Function::iterator FI = F->begin(), FE = F->end(); FI != FE; ++FI) {
BasicBlock *BB = *FI;
for (BasicBlock::iterator BI = BB->begin(); BI != BB->end();) {
Instruction *Inst = *BI;
InstVal &IV = ValueState[Inst];
@ -280,7 +293,7 @@ bool SCCP::doSCCP() {
// The new constant inherits the old name of the operator...
if (Inst->hasName() && !Const->hasName())
Const->setName(Inst->getName(), M->getSymbolTableSure());
Const->setName(Inst->getName(), F->getSymbolTableSure());
// Delete the operator now...
delete Inst;
@ -295,6 +308,10 @@ bool SCCP::doSCCP() {
}
}
// Reset state so that the next invokation will have empty data structures
BBExecutable.clear();
ValueState.clear();
// Merge identical constants last: this is important because we may have just
// introduced constants that already exist, and we don't want to pollute later
// stages with extraneous constants.
@ -457,27 +474,3 @@ void SCCP::OperandChangedState(User *U) {
visit(I);
}
namespace {
// SCCPPass - Use Sparse Conditional Constant Propogation
// to prove whether a value is constant and whether blocks are used.
//
struct SCCPPass : public FunctionPass {
const char *getPassName() const {
return "Sparse Conditional Constant Propogation";
}
inline bool runOnFunction(Function *F) {
SCCP S(F);
return S.doSCCP();
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
// FIXME: SCCP does not preserve the CFG because it folds terminators!
//AU.preservesCFG();
}
};
}
Pass *createSCCPPass() {
return new SCCPPass();
}