//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "sccp"
#include "llvm/Transforms/Scalar.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/ConstantFolding.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/IR/CallSite.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/InstVisitor.h"
#include "llvm/IR/Instructions.h"
-#include "llvm/InstVisitor.h"
#include "llvm/Pass.h"
-#include "llvm/Support/CallSite.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Utils/Local.h"
#include <algorithm>
using namespace llvm;
+#define DEBUG_TYPE "sccp"
+
STATISTIC(NumInstRemoved, "Number of instructions removed");
STATISTIC(NumDeadBlocks , "Number of basic blocks unreachable");
}
public:
- LatticeVal() : Val(0, undefined) {}
+ LatticeVal() : Val(nullptr, undefined) {}
bool isUndefined() const { return getLatticeValue() == undefined; }
bool isConstant() const {
ConstantInt *getConstantInt() const {
if (isConstant())
return dyn_cast<ConstantInt>(getConstant());
- return 0;
+ return nullptr;
}
void markForcedConstant(Constant *V) {
/// Constant Propagation.
///
class SCCPSolver : public InstVisitor<SCCPSolver> {
- const DataLayout *TD;
+ const DataLayout &DL;
const TargetLibraryInfo *TLI;
SmallPtrSet<BasicBlock*, 8> BBExecutable; // The BBs that are executable.
DenseMap<Value*, LatticeVal> ValueState; // The state each value is in.
typedef std::pair<BasicBlock*, BasicBlock*> Edge;
DenseSet<Edge> KnownFeasibleEdges;
public:
- SCCPSolver(const DataLayout *td, const TargetLibraryInfo *tli)
- : TD(td), TLI(tli) {}
+ SCCPSolver(const DataLayout &DL, const TargetLibraryInfo *tli)
+ : DL(DL), TLI(tli) {}
/// 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.
///
/// This returns true if the block was not considered live before.
bool MarkBlockExecutable(BasicBlock *BB) {
- if (!BBExecutable.insert(BB)) return false;
+ if (!BBExecutable.insert(BB).second)
+ return false;
DEBUG(dbgs() << "Marking Block Executable: " << BB->getName() << '\n');
BBWorkList.push_back(BB); // Add the block to the work list!
return true;
if (Constant *C = dyn_cast<Constant>(V)) {
Constant *Elt = C->getAggregateElement(i);
- if (Elt == 0)
+ if (!Elt)
LV.markOverdefined(); // Unknown sort of constant.
else if (isa<UndefValue>(Elt))
; // Undef values remain undefined.
void visitExtractValueInst(ExtractValueInst &EVI);
void visitInsertValueInst(InsertValueInst &IVI);
void visitLandingPadInst(LandingPadInst &I) { markAnythingOverdefined(&I); }
+ void visitCleanupPadInst(CleanupPadInst &CPI) { markAnythingOverdefined(&CPI); }
+ void visitCatchPadInst(CatchPadInst &CPI) {
+ markAnythingOverdefined(&CPI);
+ visitTerminatorInst(CPI);
+ }
// Instructions that cannot be folded away.
void visitStoreInst (StoreInst &I);
}
void visitCallSite (CallSite CS);
void visitResumeInst (TerminatorInst &I) { /*returns void*/ }
- void visitUnwindInst (TerminatorInst &I) { /*returns void*/ }
void visitUnreachableInst(TerminatorInst &I) { /*returns void*/ }
void visitFenceInst (FenceInst &I) { /*returns void*/ }
- void visitAtomicCmpXchgInst (AtomicCmpXchgInst &I) { markOverdefined(&I); }
+ void visitAtomicCmpXchgInst(AtomicCmpXchgInst &I) {
+ markAnythingOverdefined(&I);
+ }
void visitAtomicRMWInst (AtomicRMWInst &I) { markOverdefined(&I); }
void visitAllocaInst (Instruction &I) { markOverdefined(&I); }
void visitVAArgInst (Instruction &I) { markAnythingOverdefined(&I); }
LatticeVal BCValue = getValueState(BI->getCondition());
ConstantInt *CI = BCValue.getConstantInt();
- if (CI == 0) {
+ if (!CI) {
// Overdefined condition variables, and branches on unfoldable constant
// conditions, mean the branch could go either way.
if (!BCValue.isUndefined())
return;
}
- if (isa<InvokeInst>(TI)) {
- // Invoke instructions successors are always executable.
- Succs[0] = Succs[1] = true;
+ // Unwinding instructions successors are always executable.
+ if (TI.isExceptional()) {
+ Succs.assign(TI.getNumSuccessors(), true);
return;
}
LatticeVal SCValue = getValueState(SI->getCondition());
ConstantInt *CI = SCValue.getConstantInt();
- if (CI == 0) { // Overdefined or undefined condition?
+ if (!CI) { // Overdefined or undefined condition?
// All destinations are executable!
if (!SCValue.isUndefined())
Succs.assign(TI.getNumSuccessors(), true);
// Overdefined condition variables mean the branch could go either way,
// undef conditions mean that neither edge is feasible yet.
ConstantInt *CI = BCValue.getConstantInt();
- if (CI == 0)
+ if (!CI)
return !BCValue.isUndefined();
// Constant condition variables mean the branch can only go a single way.
return BI->getSuccessor(CI->isZero()) == To;
}
- // Invoke instructions successors are always executable.
- if (isa<InvokeInst>(TI))
+ // Unwinding instructions successors are always executable.
+ if (TI->isExceptional())
return true;
if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
LatticeVal SCValue = getValueState(SI->getCondition());
ConstantInt *CI = SCValue.getConstantInt();
- if (CI == 0)
+ if (!CI)
return !SCValue.isUndefined();
return SI->findCaseValue(CI).getCaseSuccessor() == To;
#ifndef NDEBUG
dbgs() << "Unknown terminator instruction: " << *TI << '\n';
#endif
- llvm_unreachable(0);
+ llvm_unreachable(nullptr);
}
// visit Implementations - Something changed in this instruction, either an
// constant. If they are constant and don't agree, the PHI is overdefined.
// If there are no executable operands, the PHI remains undefined.
//
- Constant *OperandVal = 0;
+ Constant *OperandVal = nullptr;
for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
LatticeVal IV = getValueState(PN.getIncomingValue(i));
if (IV.isUndefined()) continue; // Doesn't influence PHI node.
if (IV.isOverdefined()) // PHI node becomes overdefined!
return markOverdefined(&PN);
- if (OperandVal == 0) { // Grab the first value.
+ if (!OperandVal) { // Grab the first value.
OperandVal = IV.getConstant();
continue;
}
void SCCPSolver::visitInsertValueInst(InsertValueInst &IVI) {
StructType *STy = dyn_cast<StructType>(IVI.getType());
- if (STy == 0)
+ if (!STy)
return markOverdefined(&IVI);
// If this has more than one index, we can't handle it, drive all results to
// If this is an AND or OR with 0 or -1, it doesn't matter that the other
// operand is overdefined.
if (I.getOpcode() == Instruction::And || I.getOpcode() == Instruction::Or) {
- LatticeVal *NonOverdefVal = 0;
+ LatticeVal *NonOverdefVal = nullptr;
if (!V1State.isOverdefined())
NonOverdefVal = &V1State;
else if (!V2State.isOverdefined())
}
Constant *Ptr = Operands[0];
- ArrayRef<Constant *> Indices(Operands.begin() + 1, Operands.end());
- markConstant(&I, ConstantExpr::getGetElementPtr(Ptr, Indices));
+ auto Indices = makeArrayRef(Operands.begin() + 1, Operands.end());
+ markConstant(&I, ConstantExpr::getGetElementPtr(I.getSourceElementType(), Ptr,
+ Indices));
}
void SCCPSolver::visitStoreInst(StoreInst &SI) {
// load null -> null
if (isa<ConstantPointerNull>(Ptr) && I.getPointerAddressSpace() == 0)
- return markConstant(IV, &I, Constant::getNullValue(I.getType()));
+ return markConstant(IV, &I, UndefValue::get(I.getType()));
// Transform load (constant global) into the value loaded.
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Ptr)) {
}
// Transform load from a constant into a constant if possible.
- if (Constant *C = ConstantFoldLoadFromConstPtr(Ptr, TD))
+ if (Constant *C = ConstantFoldLoadFromConstPtr(Ptr, DL))
return markConstant(IV, &I, C);
// Otherwise we cannot say for certain what value this load will produce.
// 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->isDeclaration()) {
+ if (!F || F->isDeclaration()) {
CallOverdefined:
// Void return and not tracking callee, just bail.
if (I->getType()->isVoidTy()) return;
Operands.push_back(State.getConstant());
}
+ if (getValueState(I).isOverdefined())
+ return;
+
// If we can constant fold this, mark the result of the call as a
// constant.
if (Constant *C = ConstantFoldCall(F, Operands, TLI))
// since all of its users will have already been marked as overdefined
// Update all of the users of this instruction's value.
//
- for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
- UI != E; ++UI)
- if (Instruction *I = dyn_cast<Instruction>(*UI))
- OperandChangedState(I);
+ for (User *U : I->users())
+ if (Instruction *UI = dyn_cast<Instruction>(U))
+ OperandChangedState(UI);
}
// Process the instruction work list.
// Update all of the users of this instruction's value.
//
if (I->getType()->isStructTy() || !getValueState(I).isOverdefined())
- for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
- UI != E; ++UI)
- if (Instruction *I = dyn_cast<Instruction>(*UI))
- OperandChangedState(I);
+ for (User *U : I->users())
+ if (Instruction *UI = dyn_cast<Instruction>(U))
+ OperandChangedState(UI);
}
// Process the basic block work list.
/// Sparse Conditional Constant Propagator.
///
struct SCCP : public FunctionPass {
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addRequired<TargetLibraryInfo>();
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.addRequired<TargetLibraryInfoWrapperPass>();
+ AU.addPreserved<GlobalsAAWrapperPass>();
}
static char ID; // Pass identification, replacement for typeid
SCCP() : FunctionPass(ID) {
// runOnFunction - Run the Sparse Conditional Constant Propagation
// algorithm, and return true if the function was modified.
//
- bool runOnFunction(Function &F);
+ bool runOnFunction(Function &F) override;
};
} // end anonymous namespace
Instruction *Inst = --I;
if (!Inst->use_empty())
Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
- if (isa<LandingPadInst>(Inst)) {
+ if (Inst->isEHPad()) {
EndInst = Inst;
continue;
}
return false;
DEBUG(dbgs() << "SCCP on function '" << F.getName() << "'\n");
- const DataLayout *TD = getAnalysisIfAvailable<DataLayout>();
- const TargetLibraryInfo *TLI = &getAnalysis<TargetLibraryInfo>();
- SCCPSolver Solver(TD, TLI);
+ const DataLayout &DL = F.getParent()->getDataLayout();
+ const TargetLibraryInfo *TLI =
+ &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
+ SCCPSolver Solver(DL, TLI);
// Mark the first block of the function as being executable.
Solver.MarkBlockExecutable(F.begin());
/// Constant Propagation.
///
struct IPSCCP : public ModulePass {
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addRequired<TargetLibraryInfo>();
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.addRequired<TargetLibraryInfoWrapperPass>();
}
static char ID;
IPSCCP() : ModulePass(ID) {
initializeIPSCCPPass(*PassRegistry::getPassRegistry());
}
- bool runOnModule(Module &M);
+ bool runOnModule(Module &M) override;
};
} // end anonymous namespace
INITIALIZE_PASS_BEGIN(IPSCCP, "ipsccp",
"Interprocedural Sparse Conditional Constant Propagation",
false, false)
-INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_PASS_END(IPSCCP, "ipsccp",
"Interprocedural Sparse Conditional Constant Propagation",
false, false)
// Delete any dead constantexpr klingons.
GV->removeDeadConstantUsers();
- for (Value::const_use_iterator UI = GV->use_begin(), E = GV->use_end();
- UI != E; ++UI) {
- const User *U = *UI;
- if (const StoreInst *SI = dyn_cast<StoreInst>(U)) {
+ for (const Use &U : GV->uses()) {
+ const User *UR = U.getUser();
+ if (const StoreInst *SI = dyn_cast<StoreInst>(UR)) {
if (SI->getOperand(0) == GV || SI->isVolatile())
return true; // Storing addr of GV.
- } else if (isa<InvokeInst>(U) || isa<CallInst>(U)) {
+ } else if (isa<InvokeInst>(UR) || isa<CallInst>(UR)) {
// Make sure we are calling the function, not passing the address.
- ImmutableCallSite CS(cast<Instruction>(U));
- if (!CS.isCallee(UI))
+ ImmutableCallSite CS(cast<Instruction>(UR));
+ if (!CS.isCallee(&U))
return true;
- } else if (const LoadInst *LI = dyn_cast<LoadInst>(U)) {
+ } else if (const LoadInst *LI = dyn_cast<LoadInst>(UR)) {
if (LI->isVolatile())
return true;
- } else if (isa<BlockAddress>(U)) {
+ } else if (isa<BlockAddress>(UR)) {
// blockaddress doesn't take the address of the function, it takes addr
// of label.
} else {
}
bool IPSCCP::runOnModule(Module &M) {
- const DataLayout *TD = getAnalysisIfAvailable<DataLayout>();
- const TargetLibraryInfo *TLI = &getAnalysis<TargetLibraryInfo>();
- SCCPSolver Solver(TD, TLI);
+ const DataLayout &DL = M.getDataLayout();
+ const TargetLibraryInfo *TLI =
+ &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
+ SCCPSolver Solver(DL, TLI);
// AddressTakenFunctions - This set keeps track of the address-taken functions
// that are in the input. As IPSCCP runs through and simplifies code,
MadeChanges = true;
TerminatorInst *TI = BB->getTerminator();
- for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) {
- BasicBlock *Succ = TI->getSuccessor(i);
+ for (BasicBlock *Succ : TI->successors()) {
if (!Succ->empty() && isa<PHINode>(Succ->begin()))
- TI->getSuccessor(i)->removePredecessor(BB);
+ Succ->removePredecessor(BB);
}
if (!TI->use_empty())
TI->replaceAllUsesWith(UndefValue::get(TI->getType()));
TI->eraseFromParent();
+ new UnreachableInst(M.getContext(), BB);
if (&*BB != &F->front())
BlocksToErase.push_back(BB);
- else
- new UnreachableInst(M.getContext(), BB);
continue;
}
for (unsigned i = 0, e = BlocksToErase.size(); i != e; ++i) {
// If there are any PHI nodes in this successor, drop entries for BB now.
BasicBlock *DeadBB = BlocksToErase[i];
- for (Value::use_iterator UI = DeadBB->use_begin(), UE = DeadBB->use_end();
- UI != UE; ) {
+ for (Value::user_iterator UI = DeadBB->user_begin(),
+ UE = DeadBB->user_end();
+ UI != UE;) {
// Grab the user and then increment the iterator early, as the user
// will be deleted. Step past all adjacent uses from the same user.
Instruction *I = dyn_cast<Instruction>(*UI);
"Overdefined values should have been taken out of the map!");
DEBUG(dbgs() << "Found that GV '" << GV->getName() << "' is constant!\n");
while (!GV->use_empty()) {
- StoreInst *SI = cast<StoreInst>(GV->use_back());
+ StoreInst *SI = cast<StoreInst>(GV->user_back());
SI->eraseFromParent();
}
M.getGlobalList().erase(GV);
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