//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
#include "llvm/DerivedTypes.h"
#include "llvm/Instructions.h"
#include "llvm/Pass.h"
-#include "llvm/Support/InstVisitor.h"
+#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Support/CallSite.h"
+#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
-#include "llvm/ADT/hash_map"
+#include "llvm/Support/InstVisitor.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/STLExtras.h"
#include <algorithm>
-#include <set>
+#include <map>
using namespace llvm;
STATISTIC(NumInstRemoved, "Number of instructions removed");
STATISTIC(NumDeadBlocks , "Number of basic blocks unreachable");
-STATISTIC(IPNumInstRemoved, "Number ofinstructions removed by IPSCCP");
+STATISTIC(IPNumInstRemoved, "Number of instructions removed by IPSCCP");
STATISTIC(IPNumDeadBlocks , "Number of basic blocks unreachable by IPSCCP");
STATISTIC(IPNumArgsElimed ,"Number of arguments constant propagated by IPSCCP");
STATISTIC(IPNumGlobalConst, "Number of globals found to be constant by IPSCCP");
/// LatticeVal class - This class represents the different lattice values that
/// an LLVM value may occupy. It is a simple class with value semantics.
///
-class LatticeVal {
+class VISIBILITY_HIDDEN LatticeVal {
enum {
/// undefined - This LLVM Value has no known value yet.
undefined,
}
};
-} // end anonymous namespace
-
-
//===----------------------------------------------------------------------===//
//
/// SCCPSolver - This class is a general purpose solver for Sparse Conditional
/// Constant Propagation.
///
class SCCPSolver : public InstVisitor<SCCPSolver> {
- std::set<BasicBlock*> BBExecutable;// The basic blocks that are executable
- hash_map<Value*, LatticeVal> ValueState; // The state each value is in...
+ SmallSet<BasicBlock*, 16> BBExecutable;// The basic blocks that are executable
+ std::map<Value*, LatticeVal> ValueState; // The state each value is in.
/// GlobalValue - If we are tracking any values for the contents of a global
/// variable, we keep a mapping from the constant accessor to the element of
/// the global, to the currently known value. If the value becomes
/// overdefined, it's entry is simply removed from this map.
- hash_map<GlobalVariable*, LatticeVal> TrackedGlobals;
+ DenseMap<GlobalVariable*, LatticeVal> TrackedGlobals;
- /// TrackedFunctionRetVals - If we are tracking arguments into and the return
+ /// TrackedRetVals - If we are tracking arguments into and the return
/// value out of a function, it will have an entry in this map, indicating
/// what the known return value for the function is.
- hash_map<Function*, LatticeVal> TrackedFunctionRetVals;
+ DenseMap<Function*, LatticeVal> TrackedRetVals;
+
+ /// TrackedMultipleRetVals - Same as TrackedRetVals, but used for functions
+ /// that return multiple values.
+ std::map<std::pair<Function*, unsigned>, LatticeVal> TrackedMultipleRetVals;
// The reason for two worklists is that overdefined is the lowest state
// on the lattice, and moving things to overdefined as fast as possible
/// MarkBlockExecutable - This method can be used by clients to mark all of
/// the blocks that are known to be intrinsically live in the processed unit.
void MarkBlockExecutable(BasicBlock *BB) {
- DOUT << "Marking Block Executable: " << BB->getName() << "\n";
+ DOUT << "Marking Block Executable: " << BB->getNameStart() << "\n";
BBExecutable.insert(BB); // Basic block is executable!
BBWorkList.push_back(BB); // Add the block to the work list!
}
void AddTrackedFunction(Function *F) {
assert(F->hasInternalLinkage() && "Can only track internal functions!");
// Add an entry, F -> undef.
- TrackedFunctionRetVals[F];
+ if (const StructType *STy = dyn_cast<StructType>(F->getReturnType())) {
+ for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
+ TrackedMultipleRetVals.insert(std::make_pair(std::make_pair(F, i),
+ LatticeVal()));
+ } else
+ TrackedRetVals.insert(std::make_pair(F, LatticeVal()));
}
/// Solve - Solve for constants and executable blocks.
/// getExecutableBlocks - Once we have solved for constants, return the set of
/// blocks that is known to be executable.
- std::set<BasicBlock*> &getExecutableBlocks() {
+ SmallSet<BasicBlock*, 16> &getExecutableBlocks() {
return BBExecutable;
}
/// getValueMapping - Once we have solved for constants, return the mapping of
/// LLVM values to LatticeVals.
- hash_map<Value*, LatticeVal> &getValueMapping() {
+ std::map<Value*, LatticeVal> &getValueMapping() {
return ValueState;
}
- /// getTrackedFunctionRetVals - Get the inferred return value map.
+ /// getTrackedRetVals - Get the inferred return value map.
///
- const hash_map<Function*, LatticeVal> &getTrackedFunctionRetVals() {
- return TrackedFunctionRetVals;
+ const DenseMap<Function*, LatticeVal> &getTrackedRetVals() {
+ return TrackedRetVals;
}
/// getTrackedGlobals - Get and return the set of inferred initializers for
/// global variables.
- const hash_map<GlobalVariable*, LatticeVal> &getTrackedGlobals() {
+ const DenseMap<GlobalVariable*, LatticeVal> &getTrackedGlobals() {
return TrackedGlobals;
}
+ inline void markOverdefined(Value *V) {
+ markOverdefined(ValueState[V], V);
+ }
private:
// markConstant - Make a value be marked as "constant". If the value
// markOverdefined - Make a value be marked as "overdefined". If the
// value is not already overdefined, add it to the overdefined instruction
// work list so that the users of the instruction are updated later.
-
inline void markOverdefined(LatticeVal &IV, Value *V) {
if (IV.markOverdefined()) {
DEBUG(DOUT << "markOverdefined: ";
OverdefinedInstWorkList.push_back(V);
}
}
- inline void markOverdefined(Value *V) {
- markOverdefined(ValueState[V], V);
- }
inline void mergeInValue(LatticeVal &IV, Value *V, LatticeVal &MergeWithV) {
if (IV.isOverdefined() || MergeWithV.isUndefined())
// Instruction object, then use this accessor to get its value from the map.
//
inline LatticeVal &getValueState(Value *V) {
- hash_map<Value*, LatticeVal>::iterator I = ValueState.find(V);
+ std::map<Value*, LatticeVal>::iterator I = ValueState.find(V);
if (I != ValueState.end()) return I->second; // Common case, in the map
if (Constant *C = dyn_cast<Constant>(V)) {
if (isa<UndefValue>(V)) {
// Nothing to do, remain undefined.
} else {
- ValueState[C].markConstant(C); // Constants are constant
+ LatticeVal &LV = ValueState[C];
+ LV.markConstant(C); // Constants are constant
+ return LV;
}
}
// All others are underdefined by default...
return; // This edge is already known to be executable!
if (BBExecutable.count(Dest)) {
- DOUT << "Marking Edge Executable: " << Source->getName()
- << " -> " << Dest->getName() << "\n";
+ DOUT << "Marking Edge Executable: " << Source->getNameStart()
+ << " -> " << Dest->getNameStart() << "\n";
// The destination is already executable, but we just made an edge
// feasible that wasn't before. Revisit the PHI nodes in the block
// getFeasibleSuccessors - Return a vector of booleans to indicate which
// successors are reachable from a given terminator instruction.
//
- void getFeasibleSuccessors(TerminatorInst &TI, std::vector<bool> &Succs);
+ void getFeasibleSuccessors(TerminatorInst &TI, SmallVector<bool, 16> &Succs);
// isEdgeFeasible - Return true if the control flow edge from the 'From' basic
// block to the 'To' basic block is currently feasible...
void visitTerminatorInst(TerminatorInst &TI);
void visitCastInst(CastInst &I);
+ void visitGetResultInst(GetResultInst &GRI);
void visitSelectInst(SelectInst &I);
void visitBinaryOperator(Instruction &I);
void visitCmpInst(CmpInst &I);
- void visitShiftInst(ShiftInst &I) { visitBinaryOperator(I); }
void visitExtractElementInst(ExtractElementInst &I);
void visitInsertElementInst(InsertElementInst &I);
void visitShuffleVectorInst(ShuffleVectorInst &I);
}
};
+} // end anonymous namespace
+
+
// getFeasibleSuccessors - Return a vector of booleans to indicate which
// successors are reachable from a given terminator instruction.
//
void SCCPSolver::getFeasibleSuccessors(TerminatorInst &TI,
- std::vector<bool> &Succs) {
+ SmallVector<bool, 16> &Succs) {
Succs.resize(TI.getNumSuccessors());
if (BranchInst *BI = dyn_cast<BranchInst>(&TI)) {
if (BI->isUnconditional()) {
(SCValue.isConstant() && !isa<ConstantInt>(SCValue.getConstant()))) {
// All destinations are executable!
Succs.assign(TI.getNumSuccessors(), true);
- } else if (SCValue.isConstant()) {
- Constant *CPV = SCValue.getConstant();
- // Make sure to skip the "default value" which isn't a value
- for (unsigned i = 1, E = SI->getNumSuccessors(); i != E; ++i) {
- if (SI->getSuccessorValue(i) == CPV) {// Found the right branch...
- Succs[i] = true;
- return;
- }
- }
-
- // Constant value not equal to any of the branches... must execute
- // default branch then...
- Succs[0] = true;
- }
+ } else if (SCValue.isConstant())
+ Succs[SI->findCaseValue(cast<ConstantInt>(SCValue.getConstant()))] = true;
} else {
- cerr << "SCCP: Don't know how to handle: " << TI;
- Succs.assign(TI.getNumSuccessors(), true);
+ assert(0 && "SCCP: Don't know how to handle this terminator!");
}
}
return true;
} else if (BCValue.isConstant()) {
// Not branching on an evaluatable constant?
- if (BCValue.getConstant()->getType() != Type::Int1Ty) return true;
+ if (!isa<ConstantInt>(BCValue.getConstant())) return true;
// Constant condition variables mean the branch can only go a single way
return BI->getSuccessor(BCValue.getConstant() ==
std::multimap<PHINode*, Instruction*>::iterator I, E;
tie(I, E) = UsersOfOverdefinedPHIs.equal_range(&PN);
if (I != E) {
- std::vector<Instruction*> Users;
- Users.reserve(std::distance(I, E));
+ SmallVector<Instruction*, 16> Users;
for (; I != E; ++I) Users.push_back(I->second);
while (!Users.empty()) {
visit(Users.back());
void SCCPSolver::visitReturnInst(ReturnInst &I) {
if (I.getNumOperands() == 0) return; // Ret void
- // If we are tracking the return value of this function, merge it in.
Function *F = I.getParent()->getParent();
- if (F->hasInternalLinkage() && !TrackedFunctionRetVals.empty()) {
- hash_map<Function*, LatticeVal>::iterator TFRVI =
- TrackedFunctionRetVals.find(F);
- if (TFRVI != TrackedFunctionRetVals.end() &&
+ // If we are tracking the return value of this function, merge it in.
+ if (!F->hasInternalLinkage())
+ return;
+
+ if (!TrackedRetVals.empty() && I.getNumOperands() == 1) {
+ DenseMap<Function*, LatticeVal>::iterator TFRVI =
+ TrackedRetVals.find(F);
+ if (TFRVI != TrackedRetVals.end() &&
!TFRVI->second.isOverdefined()) {
LatticeVal &IV = getValueState(I.getOperand(0));
mergeInValue(TFRVI->second, F, IV);
+ return;
+ }
+ }
+
+ // Handle functions that return multiple values.
+ if (!TrackedMultipleRetVals.empty() && I.getNumOperands() > 1) {
+ for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i) {
+ std::map<std::pair<Function*, unsigned>, LatticeVal>::iterator
+ It = TrackedMultipleRetVals.find(std::make_pair(F, i));
+ if (It == TrackedMultipleRetVals.end()) break;
+ mergeInValue(It->second, F, getValueState(I.getOperand(i)));
}
}
}
-
void SCCPSolver::visitTerminatorInst(TerminatorInst &TI) {
- std::vector<bool> SuccFeasible;
+ SmallVector<bool, 16> SuccFeasible;
getFeasibleSuccessors(TI, SuccFeasible);
BasicBlock *BB = TI.getParent();
VState.getConstant(), I.getType()));
}
+void SCCPSolver::visitGetResultInst(GetResultInst &GRI) {
+ Value *Aggr = GRI.getOperand(0);
+
+ // If the operand to the getresult is an undef, the result is undef.
+ if (isa<UndefValue>(Aggr))
+ return;
+
+ Function *F;
+ if (CallInst *CI = dyn_cast<CallInst>(Aggr))
+ F = CI->getCalledFunction();
+ else
+ F = cast<InvokeInst>(Aggr)->getCalledFunction();
+
+ // TODO: If IPSCCP resolves the callee of this function, we could propagate a
+ // result back!
+ if (F == 0 || TrackedMultipleRetVals.empty()) {
+ markOverdefined(&GRI);
+ return;
+ }
+
+ // See if we are tracking the result of the callee.
+ std::map<std::pair<Function*, unsigned>, LatticeVal>::iterator
+ It = TrackedMultipleRetVals.find(std::make_pair(F, GRI.getIndex()));
+
+ // If not tracking this function (for example, it is a declaration) just move
+ // to overdefined.
+ if (It == TrackedMultipleRetVals.end()) {
+ markOverdefined(&GRI);
+ return;
+ }
+
+ // Otherwise, the value will be merged in here as a result of CallSite
+ // handling.
+}
+
void SCCPSolver::visitSelectInst(SelectInst &I) {
LatticeVal &CondValue = getValueState(I.getCondition());
if (CondValue.isUndefined())
// Could annihilate value.
if (I.getOpcode() == Instruction::And)
markConstant(IV, &I, Constant::getNullValue(I.getType()));
- else if (const PackedType *PT = dyn_cast<PackedType>(I.getType()))
- markConstant(IV, &I, ConstantPacked::getAllOnesValue(PT));
+ else if (const VectorType *PT = dyn_cast<VectorType>(I.getType()))
+ markConstant(IV, &I, ConstantVector::getAllOnesValue(PT));
else
markConstant(IV, &I, ConstantInt::getAllOnesValue(I.getType()));
return;
IdxState.getConstant()));
else if (ValState.isUndefined() && EltState.isConstant() &&
IdxState.isConstant())
- markConstant(&I, ConstantExpr::getInsertElement(UndefValue::get(I.getType()),
- EltState.getConstant(),
- IdxState.getConstant()));
+ markConstant(&I,ConstantExpr::getInsertElement(UndefValue::get(I.getType()),
+ EltState.getConstant(),
+ IdxState.getConstant()));
#endif
}
LatticeVal &IV = ValueState[&I];
if (IV.isOverdefined()) return;
- std::vector<Constant*> Operands;
+ SmallVector<Constant*, 8> Operands;
Operands.reserve(I.getNumOperands());
for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i) {
Constant *Ptr = Operands[0];
Operands.erase(Operands.begin()); // Erase the pointer from idx list...
- markConstant(IV, &I, ConstantExpr::getGetElementPtr(Ptr, Operands));
+ markConstant(IV, &I, ConstantExpr::getGetElementPtr(Ptr, &Operands[0],
+ Operands.size()));
}
void SCCPSolver::visitStoreInst(Instruction &SI) {
if (TrackedGlobals.empty() || !isa<GlobalVariable>(SI.getOperand(1)))
return;
GlobalVariable *GV = cast<GlobalVariable>(SI.getOperand(1));
- hash_map<GlobalVariable*, LatticeVal>::iterator I = TrackedGlobals.find(GV);
+ DenseMap<GlobalVariable*, LatticeVal>::iterator I = TrackedGlobals.find(GV);
if (I == TrackedGlobals.end() || I->second.isOverdefined()) return;
// Get the value we are storing into the global.
if (PtrVal.isUndefined()) return; // The pointer is not resolved yet!
if (PtrVal.isConstant() && !I.isVolatile()) {
Value *Ptr = PtrVal.getConstant();
- if (isa<ConstantPointerNull>(Ptr)) {
+ // TODO: Consider a target hook for valid address spaces for this xform.
+ if (isa<ConstantPointerNull>(Ptr) &&
+ cast<PointerType>(Ptr->getType())->getAddressSpace() == 0) {
// load null -> null
markConstant(IV, &I, Constant::getNullValue(I.getType()));
return;
// Transform load (constant global) into the value loaded.
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Ptr)) {
if (GV->isConstant()) {
- if (!GV->isExternal()) {
+ if (!GV->isDeclaration()) {
markConstant(IV, &I, GV->getInitializer());
return;
}
} else if (!TrackedGlobals.empty()) {
// If we are tracking this global, merge in the known value for it.
- hash_map<GlobalVariable*, LatticeVal>::iterator It =
+ DenseMap<GlobalVariable*, LatticeVal>::iterator It =
TrackedGlobals.find(GV);
if (It != TrackedGlobals.end()) {
mergeInValue(IV, &I, It->second);
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr))
if (CE->getOpcode() == Instruction::GetElementPtr)
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(CE->getOperand(0)))
- if (GV->isConstant() && !GV->isExternal())
+ if (GV->isConstant() && !GV->isDeclaration())
if (Constant *V =
ConstantFoldLoadThroughGEPConstantExpr(GV->getInitializer(), CE)) {
markConstant(IV, &I, V);
void SCCPSolver::visitCallSite(CallSite CS) {
Function *F = CS.getCalledFunction();
-
- // If we are tracking this function, we must make sure to bind arguments as
- // appropriate.
- hash_map<Function*, LatticeVal>::iterator TFRVI =TrackedFunctionRetVals.end();
- if (F && F->hasInternalLinkage())
- TFRVI = TrackedFunctionRetVals.find(F);
-
- if (TFRVI != TrackedFunctionRetVals.end()) {
- // If this is the first call to the function hit, mark its entry block
- // executable.
- if (!BBExecutable.count(F->begin()))
- MarkBlockExecutable(F->begin());
-
- CallSite::arg_iterator CAI = CS.arg_begin();
- for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
- AI != E; ++AI, ++CAI) {
- LatticeVal &IV = ValueState[AI];
- if (!IV.isOverdefined())
- mergeInValue(IV, AI, getValueState(*CAI));
- }
- }
Instruction *I = CS.getInstruction();
- if (I->getType() == Type::VoidTy) return;
-
- LatticeVal &IV = ValueState[I];
- if (IV.isOverdefined()) return;
-
- // Propagate the return value of the function to the value of the instruction.
- if (TFRVI != TrackedFunctionRetVals.end()) {
- mergeInValue(IV, I, TFRVI->second);
- return;
- }
+
+ // The common case is that we aren't tracking the callee, either because we
+ // are not doing interprocedural analysis or the callee is indirect, or is
+ // external. Handle these cases first.
+ if (F == 0 || !F->hasInternalLinkage()) {
+CallOverdefined:
+ // Void return and not tracking callee, just bail.
+ if (I->getType() == Type::VoidTy) return;
+
+ // Otherwise, if we have a single return value case, and if the function is
+ // a declaration, maybe we can constant fold it.
+ if (!isa<StructType>(I->getType()) && F && F->isDeclaration() &&
+ canConstantFoldCallTo(F)) {
+
+ SmallVector<Constant*, 8> Operands;
+ for (CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end();
+ AI != E; ++AI) {
+ LatticeVal &State = getValueState(*AI);
+ if (State.isUndefined())
+ return; // Operands are not resolved yet.
+ else if (State.isOverdefined()) {
+ markOverdefined(I);
+ return;
+ }
+ assert(State.isConstant() && "Unknown state!");
+ Operands.push_back(State.getConstant());
+ }
+
+ // If we can constant fold this, mark the result of the call as a
+ // constant.
+ if (Constant *C = ConstantFoldCall(F, &Operands[0], Operands.size())) {
+ markConstant(I, C);
+ return;
+ }
+ }
- if (F == 0 || !F->isExternal() || !canConstantFoldCallTo(F)) {
- markOverdefined(IV, I);
+ // Otherwise, we don't know anything about this call, mark it overdefined.
+ markOverdefined(I);
return;
}
- std::vector<Constant*> Operands;
- Operands.reserve(I->getNumOperands()-1);
-
- for (CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end();
- AI != E; ++AI) {
- LatticeVal &State = getValueState(*AI);
- if (State.isUndefined())
- return; // Operands are not resolved yet...
- else if (State.isOverdefined()) {
- markOverdefined(IV, I);
- return;
+ // If this is a single/zero retval case, see if we're tracking the function.
+ const StructType *RetSTy = dyn_cast<StructType>(I->getType());
+ if (RetSTy == 0) {
+ // Check to see if we're tracking this callee, if not, handle it in the
+ // common path above.
+ DenseMap<Function*, LatticeVal>::iterator TFRVI = TrackedRetVals.find(F);
+ if (TFRVI == TrackedRetVals.end())
+ goto CallOverdefined;
+
+ // If so, propagate the return value of the callee into this call result.
+ mergeInValue(I, TFRVI->second);
+ } else {
+ // Check to see if we're tracking this callee, if not, handle it in the
+ // common path above.
+ std::map<std::pair<Function*, unsigned>, LatticeVal>::iterator
+ TMRVI = TrackedMultipleRetVals.find(std::make_pair(F, 0));
+ if (TMRVI == TrackedMultipleRetVals.end())
+ goto CallOverdefined;
+
+ // If we are tracking this callee, propagate the return values of the call
+ // into this call site. We do this by walking all the getresult uses.
+ for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
+ UI != E; ++UI) {
+ GetResultInst *GRI = cast<GetResultInst>(*UI);
+ mergeInValue(GRI,
+ TrackedMultipleRetVals[std::make_pair(F, GRI->getIndex())]);
}
- assert(State.isConstant() && "Unknown state!");
- Operands.push_back(State.getConstant());
}
-
- if (Constant *C = ConstantFoldCall(F, Operands))
- markConstant(IV, I, C);
- else
- markOverdefined(IV, I);
+
+ // Finally, if this is the first call to the function hit, mark its entry
+ // block executable.
+ if (!BBExecutable.count(F->begin()))
+ MarkBlockExecutable(F->begin());
+
+ // Propagate information from this call site into the callee.
+ CallSite::arg_iterator CAI = CS.arg_begin();
+ for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
+ AI != E; ++AI, ++CAI) {
+ LatticeVal &IV = ValueState[AI];
+ if (!IV.isOverdefined())
+ mergeInValue(IV, AI, getValueState(*CAI));
+ }
}
case Instruction::Or:
// undef | X -> -1. X could be -1.
- if (const PackedType *PTy = dyn_cast<PackedType>(ITy))
- markForcedConstant(LV, I, ConstantPacked::getAllOnesValue(PTy));
+ if (const VectorType *PTy = dyn_cast<VectorType>(ITy))
+ markForcedConstant(LV, I, ConstantVector::getAllOnesValue(PTy));
else
markForcedConstant(LV, I, ConstantInt::getAllOnesValue(ITy));
return true;
continue;
}
- // If the edge to the first successor isn't thought to be feasible yet, mark
- // it so now.
- if (KnownFeasibleEdges.count(Edge(BB, TI->getSuccessor(0))))
+ // If the edge to the second successor isn't thought to be feasible yet,
+ // mark it so now. We pick the second one so that this goes to some
+ // enumerated value in a switch instead of going to the default destination.
+ if (KnownFeasibleEdges.count(Edge(BB, TI->getSuccessor(1))))
continue;
// Otherwise, it isn't already thought to be feasible. Mark it as such now
// and return. This will make other blocks reachable, which will allow new
// values to be discovered and existing ones to be moved in the lattice.
- markEdgeExecutable(BB, TI->getSuccessor(0));
+ markEdgeExecutable(BB, TI->getSuccessor(1));
+
+ // This must be a conditional branch of switch on undef. At this point,
+ // force the old terminator to branch to the first successor. This is
+ // required because we are now influencing the dataflow of the function with
+ // the assumption that this edge is taken. If we leave the branch condition
+ // as undef, then further analysis could think the undef went another way
+ // leading to an inconsistent set of conclusions.
+ if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
+ BI->setCondition(ConstantInt::getFalse());
+ } else {
+ SwitchInst *SI = cast<SwitchInst>(TI);
+ SI->setCondition(SI->getCaseValue(1));
+ }
+
return true;
}
/// SCCP Class - This class uses the SCCPSolver to implement a per-function
/// Sparse Conditional Constant Propagator.
///
- struct SCCP : public FunctionPass {
+ struct VISIBILITY_HIDDEN SCCP : public FunctionPass {
+ static char ID; // Pass identification, replacement for typeid
+ SCCP() : FunctionPass((intptr_t)&ID) {}
+
// runOnFunction - Run the Sparse Conditional Constant Propagation
// algorithm, and return true if the function was modified.
//
AU.setPreservesCFG();
}
};
-
- RegisterPass<SCCP> X("sccp", "Sparse Conditional Constant Propagation");
} // end anonymous namespace
+char SCCP::ID = 0;
+static RegisterPass<SCCP>
+X("sccp", "Sparse Conditional Constant Propagation");
// createSCCPPass - This is the public interface to this file...
FunctionPass *llvm::createSCCPPass() {
// and return true if the function was modified.
//
bool SCCP::runOnFunction(Function &F) {
- DOUT << "SCCP on function '" << F.getName() << "'\n";
+ DOUT << "SCCP on function '" << F.getNameStart() << "'\n";
SCCPSolver Solver;
// Mark the first block of the function as being executable.
Solver.MarkBlockExecutable(F.begin());
// Mark all arguments to the function as being overdefined.
- hash_map<Value*, LatticeVal> &Values = Solver.getValueMapping();
- for (Function::arg_iterator AI = F.arg_begin(), E = F.arg_end(); AI != E; ++AI)
- Values[AI].markOverdefined();
+ for (Function::arg_iterator AI = F.arg_begin(), E = F.arg_end(); AI != E;++AI)
+ Solver.markOverdefined(AI);
// Solve for constants.
bool ResolvedUndefs = true;
// delete their contents now. Note that we cannot actually delete the blocks,
// as we cannot modify the CFG of the function.
//
- std::set<BasicBlock*> &ExecutableBBs = Solver.getExecutableBlocks();
+ SmallSet<BasicBlock*, 16> &ExecutableBBs = Solver.getExecutableBlocks();
+ SmallVector<Instruction*, 32> Insts;
+ std::map<Value*, LatticeVal> &Values = Solver.getValueMapping();
+
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
if (!ExecutableBBs.count(BB)) {
DOUT << " BasicBlock Dead:" << *BB;
// Delete the instructions backwards, as it has a reduced likelihood of
// having to update as many def-use and use-def chains.
- std::vector<Instruction*> Insts;
for (BasicBlock::iterator I = BB->begin(), E = BB->getTerminator();
I != E; ++I)
Insts.push_back(I);
//
for (BasicBlock::iterator BI = BB->begin(), E = BB->end(); BI != E; ) {
Instruction *Inst = BI++;
- if (Inst->getType() != Type::VoidTy) {
- LatticeVal &IV = Values[Inst];
- if (IV.isConstant() || IV.isUndefined() &&
- !isa<TerminatorInst>(Inst)) {
- Constant *Const = IV.isConstant()
- ? IV.getConstant() : UndefValue::get(Inst->getType());
- DOUT << " Constant: " << *Const << " = " << *Inst;
-
- // Replaces all of the uses of a variable with uses of the constant.
- Inst->replaceAllUsesWith(Const);
-
- // Delete the instruction.
- BB->getInstList().erase(Inst);
+ if (Inst->getType() == Type::VoidTy ||
+ isa<StructType>(Inst->getType()) ||
+ isa<TerminatorInst>(Inst))
+ continue;
+
+ LatticeVal &IV = Values[Inst];
+ if (!IV.isConstant() && !IV.isUndefined())
+ continue;
+
+ Constant *Const = IV.isConstant()
+ ? IV.getConstant() : UndefValue::get(Inst->getType());
+ DOUT << " Constant: " << *Const << " = " << *Inst;
- // Hey, we just changed something!
- MadeChanges = true;
- ++NumInstRemoved;
- }
- }
+ // Replaces all of the uses of a variable with uses of the constant.
+ Inst->replaceAllUsesWith(Const);
+
+ // Delete the instruction.
+ Inst->eraseFromParent();
+
+ // Hey, we just changed something!
+ MadeChanges = true;
+ ++NumInstRemoved;
}
}
/// IPSCCP Class - This class implements interprocedural Sparse Conditional
/// Constant Propagation.
///
- struct IPSCCP : public ModulePass {
+ struct VISIBILITY_HIDDEN IPSCCP : public ModulePass {
+ static char ID;
+ IPSCCP() : ModulePass((intptr_t)&ID) {}
bool runOnModule(Module &M);
};
-
- RegisterPass<IPSCCP>
- Y("ipsccp", "Interprocedural Sparse Conditional Constant Propagation");
} // end anonymous namespace
+char IPSCCP::ID = 0;
+static RegisterPass<IPSCCP>
+Y("ipsccp", "Interprocedural Sparse Conditional Constant Propagation");
+
// createIPSCCPPass - This is the public interface to this file...
ModulePass *llvm::createIPSCCPPass() {
return new IPSCCP();
// Loop over all functions, marking arguments to those with their addresses
// taken or that are external as overdefined.
//
- hash_map<Value*, LatticeVal> &Values = Solver.getValueMapping();
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
if (!F->hasInternalLinkage() || AddressIsTaken(F)) {
- if (!F->isExternal())
+ if (!F->isDeclaration())
Solver.MarkBlockExecutable(F->begin());
for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
AI != E; ++AI)
- Values[AI].markOverdefined();
+ Solver.markOverdefined(AI);
} else {
Solver.AddTrackedFunction(F);
}
// Iterate over all of the instructions in the module, replacing them with
// constants if we have found them to be of constant values.
//
- std::set<BasicBlock*> &ExecutableBBs = Solver.getExecutableBlocks();
+ SmallSet<BasicBlock*, 16> &ExecutableBBs = Solver.getExecutableBlocks();
+ SmallVector<Instruction*, 32> Insts;
+ SmallVector<BasicBlock*, 32> BlocksToErase;
+ std::map<Value*, LatticeVal> &Values = Solver.getValueMapping();
+
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
AI != E; ++AI)
}
}
- std::vector<BasicBlock*> BlocksToErase;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
if (!ExecutableBBs.count(BB)) {
DOUT << " BasicBlock Dead:" << *BB;
// Delete the instructions backwards, as it has a reduced likelihood of
// having to update as many def-use and use-def chains.
- std::vector<Instruction*> Insts;
TerminatorInst *TI = BB->getTerminator();
for (BasicBlock::iterator I = BB->begin(), E = TI; I != E; ++I)
Insts.push_back(I);
for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) {
BasicBlock *Succ = TI->getSuccessor(i);
- if (Succ->begin() != Succ->end() && isa<PHINode>(Succ->begin()))
+ if (!Succ->empty() && isa<PHINode>(Succ->begin()))
TI->getSuccessor(i)->removePredecessor(BB);
}
if (!TI->use_empty())
} else {
for (BasicBlock::iterator BI = BB->begin(), E = BB->end(); BI != E; ) {
Instruction *Inst = BI++;
- if (Inst->getType() != Type::VoidTy) {
- LatticeVal &IV = Values[Inst];
- if (IV.isConstant() || IV.isUndefined() &&
- !isa<TerminatorInst>(Inst)) {
- Constant *Const = IV.isConstant()
- ? IV.getConstant() : UndefValue::get(Inst->getType());
- DOUT << " Constant: " << *Const << " = " << *Inst;
-
- // Replaces all of the uses of a variable with uses of the
- // constant.
- Inst->replaceAllUsesWith(Const);
-
- // Delete the instruction.
- if (!isa<TerminatorInst>(Inst) && !isa<CallInst>(Inst))
- BB->getInstList().erase(Inst);
-
- // Hey, we just changed something!
- MadeChanges = true;
- ++IPNumInstRemoved;
- }
- }
+ if (Inst->getType() == Type::VoidTy ||
+ isa<StructType>(Inst->getType()) ||
+ isa<TerminatorInst>(Inst))
+ continue;
+
+ LatticeVal &IV = Values[Inst];
+ if (!IV.isConstant() && !IV.isUndefined())
+ continue;
+
+ Constant *Const = IV.isConstant()
+ ? IV.getConstant() : UndefValue::get(Inst->getType());
+ DOUT << " Constant: " << *Const << " = " << *Inst;
+
+ // Replaces all of the uses of a variable with uses of the
+ // constant.
+ Inst->replaceAllUsesWith(Const);
+
+ // Delete the instruction.
+ if (!isa<CallInst>(Inst))
+ Inst->eraseFromParent();
+
+ // Hey, we just changed something!
+ MadeChanges = true;
+ ++IPNumInstRemoved;
}
}
// Make this an uncond branch to the first successor.
TerminatorInst *TI = I->getParent()->getTerminator();
- new BranchInst(TI->getSuccessor(0), TI);
+ BranchInst::Create(TI->getSuccessor(0), TI);
// Remove entries in successor phi nodes to remove edges.
for (unsigned i = 1, e = TI->getNumSuccessors(); i != e; ++i)
// Finally, delete the basic block.
F->getBasicBlockList().erase(DeadBB);
}
+ BlocksToErase.clear();
}
// If we inferred constant or undef return values for a function, we replaced
// all call uses with the inferred value. This means we don't need to bother
// actually returning anything from the function. Replace all return
// instructions with return undef.
- const hash_map<Function*, LatticeVal> &RV =Solver.getTrackedFunctionRetVals();
- for (hash_map<Function*, LatticeVal>::const_iterator I = RV.begin(),
+ // TODO: Process multiple value ret instructions also.
+ const DenseMap<Function*, LatticeVal> &RV = Solver.getTrackedRetVals();
+ for (DenseMap<Function*, LatticeVal>::const_iterator I = RV.begin(),
E = RV.end(); I != E; ++I)
if (!I->second.isOverdefined() &&
I->first->getReturnType() != Type::VoidTy) {
// If we infered constant or undef values for globals variables, we can delete
// the global and any stores that remain to it.
- const hash_map<GlobalVariable*, LatticeVal> &TG = Solver.getTrackedGlobals();
- for (hash_map<GlobalVariable*, LatticeVal>::const_iterator I = TG.begin(),
+ const DenseMap<GlobalVariable*, LatticeVal> &TG = Solver.getTrackedGlobals();
+ for (DenseMap<GlobalVariable*, LatticeVal>::const_iterator I = TG.begin(),
E = TG.end(); I != E; ++I) {
GlobalVariable *GV = I->first;
assert(!I->second.isOverdefined() &&
"Overdefined values should have been taken out of the map!");
- DOUT << "Found that GV '" << GV->getName()<< "' is constant!\n";
+ DOUT << "Found that GV '" << GV->getNameStart() << "' is constant!\n";
while (!GV->use_empty()) {
StoreInst *SI = cast<StoreInst>(GV->use_back());
SI->eraseFromParent();