#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/Loads.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/MemoryDependenceAnalysis.h"
#include "llvm/Analysis/PHITransAddr.h"
static cl::opt<bool> EnablePRE("enable-pre",
cl::init(true), cl::Hidden);
static cl::opt<bool> EnableLoadPRE("enable-load-pre", cl::init(true));
+static cl::opt<bool> EnableFullLoadPRE("enable-full-load-pre", cl::init(false));
//===----------------------------------------------------------------------===//
// ValueTable Class
/// two values.
namespace {
struct Expression {
- enum ExpressionOpcode { ADD, FADD, SUB, FSUB, MUL, FMUL,
- UDIV, SDIV, FDIV, UREM, SREM,
- FREM, SHL, LSHR, ASHR, AND, OR, XOR, ICMPEQ,
- ICMPNE, ICMPUGT, ICMPUGE, ICMPULT, ICMPULE,
- ICMPSGT, ICMPSGE, ICMPSLT, ICMPSLE, FCMPOEQ,
- FCMPOGT, FCMPOGE, FCMPOLT, FCMPOLE, FCMPONE,
- FCMPORD, FCMPUNO, FCMPUEQ, FCMPUGT, FCMPUGE,
- FCMPULT, FCMPULE, FCMPUNE, EXTRACT, INSERT,
- SHUFFLE, SELECT, TRUNC, ZEXT, SEXT, FPTOUI,
- FPTOSI, UITOFP, SITOFP, FPTRUNC, FPEXT,
- PTRTOINT, INTTOPTR, BITCAST, GEP, CALL, CONSTANT,
- INSERTVALUE, EXTRACTVALUE, EMPTY, TOMBSTONE };
+ enum ExpressionOpcode {
+ ADD = Instruction::Add,
+ FADD = Instruction::FAdd,
+ SUB = Instruction::Sub,
+ FSUB = Instruction::FSub,
+ MUL = Instruction::Mul,
+ FMUL = Instruction::FMul,
+ UDIV = Instruction::UDiv,
+ SDIV = Instruction::SDiv,
+ FDIV = Instruction::FDiv,
+ UREM = Instruction::URem,
+ SREM = Instruction::SRem,
+ FREM = Instruction::FRem,
+ SHL = Instruction::Shl,
+ LSHR = Instruction::LShr,
+ ASHR = Instruction::AShr,
+ AND = Instruction::And,
+ OR = Instruction::Or,
+ XOR = Instruction::Xor,
+ TRUNC = Instruction::Trunc,
+ ZEXT = Instruction::ZExt,
+ SEXT = Instruction::SExt,
+ FPTOUI = Instruction::FPToUI,
+ FPTOSI = Instruction::FPToSI,
+ UITOFP = Instruction::UIToFP,
+ SITOFP = Instruction::SIToFP,
+ FPTRUNC = Instruction::FPTrunc,
+ FPEXT = Instruction::FPExt,
+ PTRTOINT = Instruction::PtrToInt,
+ INTTOPTR = Instruction::IntToPtr,
+ BITCAST = Instruction::BitCast,
+ ICMPEQ, ICMPNE, ICMPUGT, ICMPUGE, ICMPULT, ICMPULE,
+ ICMPSGT, ICMPSGE, ICMPSLT, ICMPSLE, FCMPOEQ,
+ FCMPOGT, FCMPOGE, FCMPOLT, FCMPOLE, FCMPONE,
+ FCMPORD, FCMPUNO, FCMPUEQ, FCMPUGT, FCMPUGE,
+ FCMPULT, FCMPULE, FCMPUNE, EXTRACT, INSERT,
+ SHUFFLE, SELECT, GEP, CALL, CONSTANT,
+ INSERTVALUE, EXTRACTVALUE, EMPTY, TOMBSTONE };
ExpressionOpcode opcode;
const Type* type;
uint32_t nextValueNumber;
- Expression::ExpressionOpcode getOpcode(BinaryOperator* BO);
Expression::ExpressionOpcode getOpcode(CmpInst* C);
- Expression::ExpressionOpcode getOpcode(CastInst* C);
Expression create_expression(BinaryOperator* BO);
Expression create_expression(CmpInst* C);
Expression create_expression(ShuffleVectorInst* V);
//===----------------------------------------------------------------------===//
// ValueTable Internal Functions
//===----------------------------------------------------------------------===//
-Expression::ExpressionOpcode ValueTable::getOpcode(BinaryOperator* BO) {
- switch(BO->getOpcode()) {
- default: // THIS SHOULD NEVER HAPPEN
- llvm_unreachable("Binary operator with unknown opcode?");
- case Instruction::Add: return Expression::ADD;
- case Instruction::FAdd: return Expression::FADD;
- case Instruction::Sub: return Expression::SUB;
- case Instruction::FSub: return Expression::FSUB;
- case Instruction::Mul: return Expression::MUL;
- case Instruction::FMul: return Expression::FMUL;
- case Instruction::UDiv: return Expression::UDIV;
- case Instruction::SDiv: return Expression::SDIV;
- case Instruction::FDiv: return Expression::FDIV;
- case Instruction::URem: return Expression::UREM;
- case Instruction::SRem: return Expression::SREM;
- case Instruction::FRem: return Expression::FREM;
- case Instruction::Shl: return Expression::SHL;
- case Instruction::LShr: return Expression::LSHR;
- case Instruction::AShr: return Expression::ASHR;
- case Instruction::And: return Expression::AND;
- case Instruction::Or: return Expression::OR;
- case Instruction::Xor: return Expression::XOR;
- }
-}
Expression::ExpressionOpcode ValueTable::getOpcode(CmpInst* C) {
if (isa<ICmpInst>(C)) {
}
}
-Expression::ExpressionOpcode ValueTable::getOpcode(CastInst* C) {
- switch(C->getOpcode()) {
- default: // THIS SHOULD NEVER HAPPEN
- llvm_unreachable("Cast operator with unknown opcode?");
- case Instruction::Trunc: return Expression::TRUNC;
- case Instruction::ZExt: return Expression::ZEXT;
- case Instruction::SExt: return Expression::SEXT;
- case Instruction::FPToUI: return Expression::FPTOUI;
- case Instruction::FPToSI: return Expression::FPTOSI;
- case Instruction::UIToFP: return Expression::UITOFP;
- case Instruction::SIToFP: return Expression::SITOFP;
- case Instruction::FPTrunc: return Expression::FPTRUNC;
- case Instruction::FPExt: return Expression::FPEXT;
- case Instruction::PtrToInt: return Expression::PTRTOINT;
- case Instruction::IntToPtr: return Expression::INTTOPTR;
- case Instruction::BitCast: return Expression::BITCAST;
- }
-}
-
Expression ValueTable::create_expression(CallInst* C) {
Expression e;
e.function = C->getCalledFunction();
e.opcode = Expression::CALL;
- for (CallInst::op_iterator I = C->op_begin()+1, E = C->op_end();
+ CallSite CS(C);
+ for (CallInst::op_iterator I = CS.arg_begin(), E = CS.arg_end();
I != E; ++I)
e.varargs.push_back(lookup_or_add(*I));
e.varargs.push_back(lookup_or_add(BO->getOperand(1)));
e.function = 0;
e.type = BO->getType();
- e.opcode = getOpcode(BO);
+ e.opcode = static_cast<Expression::ExpressionOpcode>(BO->getOpcode());
return e;
}
e.varargs.push_back(lookup_or_add(C->getOperand(0)));
e.function = 0;
e.type = C->getType();
- e.opcode = getOpcode(C);
+ e.opcode = static_cast<Expression::ExpressionOpcode>(C->getOpcode());
return e;
}
if (local_dep.isDef()) {
CallInst* local_cdep = cast<CallInst>(local_dep.getInst());
- if (local_cdep->getNumOperands() != C->getNumOperands()) {
+ if (local_cdep->getNumArgOperands() != C->getNumArgOperands()) {
valueNumbering[C] = nextValueNumber;
return nextValueNumber++;
}
- for (unsigned i = 1; i < C->getNumOperands(); ++i) {
- uint32_t c_vn = lookup_or_add(C->getOperand(i));
- uint32_t cd_vn = lookup_or_add(local_cdep->getOperand(i));
+ for (unsigned i = 0, e = C->getNumArgOperands(); i < e; ++i) {
+ uint32_t c_vn = lookup_or_add(C->getArgOperand(i));
+ uint32_t cd_vn = lookup_or_add(local_cdep->getArgOperand(i));
if (c_vn != cd_vn) {
valueNumbering[C] = nextValueNumber;
return nextValueNumber++;
return nextValueNumber++;
}
- if (cdep->getNumOperands() != C->getNumOperands()) {
+ if (cdep->getNumArgOperands() != C->getNumArgOperands()) {
valueNumbering[C] = nextValueNumber;
return nextValueNumber++;
}
- for (unsigned i = 1; i < C->getNumOperands(); ++i) {
- uint32_t c_vn = lookup_or_add(C->getOperand(i));
- uint32_t cd_vn = lookup_or_add(cdep->getOperand(i));
+ for (unsigned i = 0, e = C->getNumArgOperands(); i < e; ++i) {
+ uint32_t c_vn = lookup_or_add(C->getArgOperand(i));
+ uint32_t cd_vn = lookup_or_add(cdep->getArgOperand(i));
if (c_vn != cd_vn) {
valueNumbering[C] = nextValueNumber;
return nextValueNumber++;
bool runOnFunction(Function &F);
public:
static char ID; // Pass identification, replacement for typeid
- explicit GVN(bool nopre = false, bool noloads = false)
- : FunctionPass(&ID), NoPRE(nopre), NoLoads(noloads), MD(0) { }
+ explicit GVN(bool noloads = false)
+ : FunctionPass(&ID), NoLoads(noloads), MD(0) { }
private:
- bool NoPRE;
bool NoLoads;
MemoryDependenceAnalysis *MD;
DominatorTree *DT;
ValueTable VN;
DenseMap<BasicBlock*, ValueNumberScope*> localAvail;
+ // List of critical edges to be split between iterations.
+ SmallVector<std::pair<TerminatorInst*, unsigned>, 4> toSplit;
+
// This transformation requires dominator postdominator info
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<DominatorTree>();
Value *lookupNumber(BasicBlock *BB, uint32_t num);
void cleanupGlobalSets();
void verifyRemoved(const Instruction *I) const;
+ bool splitCriticalEdges();
};
char GVN::ID = 0;
}
// createGVNPass - The public interface to this file...
-FunctionPass *llvm::createGVNPass(bool NoPRE, bool NoLoads) {
- return new GVN(NoPRE, NoLoads);
+FunctionPass *llvm::createGVNPass(bool NoLoads) {
+ return new GVN(NoLoads);
}
static RegisterPass<GVN> X("gvn",
const TargetData &TD) {
// If the loaded or stored value is an first class array or struct, don't try
// to transform them. We need to be able to bitcast to integer.
- if (isa<StructType>(LoadTy) || isa<ArrayType>(LoadTy) ||
- isa<StructType>(StoredVal->getType()) ||
- isa<ArrayType>(StoredVal->getType()))
+ if (LoadTy->isStructTy() || LoadTy->isArrayTy() ||
+ StoredVal->getType()->isStructTy() ||
+ StoredVal->getType()->isArrayTy())
return false;
// The store has to be at least as big as the load.
const Type *StoredValTy = StoredVal->getType();
- uint64_t StoreSize = TD.getTypeSizeInBits(StoredValTy);
+ uint64_t StoreSize = TD.getTypeStoreSizeInBits(StoredValTy);
uint64_t LoadSize = TD.getTypeSizeInBits(LoadedTy);
// If the store and reload are the same size, we can always reuse it.
if (StoreSize == LoadSize) {
- if (isa<PointerType>(StoredValTy) && isa<PointerType>(LoadedTy)) {
+ if (StoredValTy->isPointerTy() && LoadedTy->isPointerTy()) {
// Pointer to Pointer -> use bitcast.
return new BitCastInst(StoredVal, LoadedTy, "", InsertPt);
}
// Convert source pointers to integers, which can be bitcast.
- if (isa<PointerType>(StoredValTy)) {
+ if (StoredValTy->isPointerTy()) {
StoredValTy = TD.getIntPtrType(StoredValTy->getContext());
StoredVal = new PtrToIntInst(StoredVal, StoredValTy, "", InsertPt);
}
const Type *TypeToCastTo = LoadedTy;
- if (isa<PointerType>(TypeToCastTo))
+ if (TypeToCastTo->isPointerTy())
TypeToCastTo = TD.getIntPtrType(StoredValTy->getContext());
if (StoredValTy != TypeToCastTo)
StoredVal = new BitCastInst(StoredVal, TypeToCastTo, "", InsertPt);
// Cast to pointer if the load needs a pointer type.
- if (isa<PointerType>(LoadedTy))
+ if (LoadedTy->isPointerTy())
StoredVal = new IntToPtrInst(StoredVal, LoadedTy, "", InsertPt);
return StoredVal;
assert(StoreSize >= LoadSize && "CanCoerceMustAliasedValueToLoad fail");
// Convert source pointers to integers, which can be manipulated.
- if (isa<PointerType>(StoredValTy)) {
+ if (StoredValTy->isPointerTy()) {
StoredValTy = TD.getIntPtrType(StoredValTy->getContext());
StoredVal = new PtrToIntInst(StoredVal, StoredValTy, "", InsertPt);
}
// Convert vectors and fp to integer, which can be manipulated.
- if (!isa<IntegerType>(StoredValTy)) {
+ if (!StoredValTy->isIntegerTy()) {
StoredValTy = IntegerType::get(StoredValTy->getContext(), StoreSize);
StoredVal = new BitCastInst(StoredVal, StoredValTy, "", InsertPt);
}
return StoredVal;
// If the result is a pointer, inttoptr.
- if (isa<PointerType>(LoadedTy))
+ if (LoadedTy->isPointerTy())
return new IntToPtrInst(StoredVal, LoadedTy, "inttoptr", InsertPt);
// Otherwise, bitcast.
const TargetData &TD) {
// If the loaded or stored value is an first class array or struct, don't try
// to transform them. We need to be able to bitcast to integer.
- if (isa<StructType>(LoadTy) || isa<ArrayType>(LoadTy))
+ if (LoadTy->isStructTy() || LoadTy->isArrayTy())
return -1;
int64_t StoreOffset = 0, LoadOffset = 0;
// If the load and store are to the exact same address, they should have been
// a must alias. AA must have gotten confused.
- // FIXME: Study to see if/when this happens.
- if (LoadOffset == StoreOffset) {
+ // FIXME: Study to see if/when this happens. One case is forwarding a memset
+ // to a load from the base of the memset.
#if 0
+ if (LoadOffset == StoreOffset) {
dbgs() << "STORE/LOAD DEP WITH COMMON POINTER MISSED:\n"
<< "Base = " << *StoreBase << "\n"
<< "Store Ptr = " << *WritePtr << "\n"
<< "Store Offs = " << StoreOffset << "\n"
<< "Load Ptr = " << *LoadPtr << "\n";
abort();
-#endif
- return -1;
}
+#endif
// If the load and store don't overlap at all, the store doesn't provide
// anything to the load. In this case, they really don't alias at all, AA
bool isAAFailure = false;
- if (StoreOffset < LoadOffset) {
+ if (StoreOffset < LoadOffset)
isAAFailure = StoreOffset+int64_t(StoreSize) <= LoadOffset;
- } else {
+ else
isAAFailure = LoadOffset+int64_t(LoadSize) <= StoreOffset;
- }
+
if (isAAFailure) {
#if 0
dbgs() << "STORE LOAD DEP WITH COMMON BASE:\n"
StoreInst *DepSI,
const TargetData &TD) {
// Cannot handle reading from store of first-class aggregate yet.
- if (isa<StructType>(DepSI->getOperand(0)->getType()) ||
- isa<ArrayType>(DepSI->getOperand(0)->getType()))
+ if (DepSI->getOperand(0)->getType()->isStructTy() ||
+ DepSI->getOperand(0)->getType()->isArrayTy())
return -1;
Value *StorePtr = DepSI->getPointerOperand();
Instruction *InsertPt, const TargetData &TD){
LLVMContext &Ctx = SrcVal->getType()->getContext();
- uint64_t StoreSize = TD.getTypeSizeInBits(SrcVal->getType())/8;
- uint64_t LoadSize = TD.getTypeSizeInBits(LoadTy)/8;
+ uint64_t StoreSize = (TD.getTypeSizeInBits(SrcVal->getType()) + 7) / 8;
+ uint64_t LoadSize = (TD.getTypeSizeInBits(LoadTy) + 7) / 8;
IRBuilder<> Builder(InsertPt->getParent(), InsertPt);
// Compute which bits of the stored value are being used by the load. Convert
// to an integer type to start with.
- if (isa<PointerType>(SrcVal->getType()))
+ if (SrcVal->getType()->isPointerTy())
SrcVal = Builder.CreatePtrToInt(SrcVal, TD.getIntPtrType(Ctx), "tmp");
- if (!isa<IntegerType>(SrcVal->getType()))
+ if (!SrcVal->getType()->isIntegerTy())
SrcVal = Builder.CreateBitCast(SrcVal, IntegerType::get(Ctx, StoreSize*8),
"tmp");
return ConstantFoldLoadFromConstPtr(Src, &TD);
}
-
+namespace {
struct AvailableValueInBlock {
/// BB - The basic block in question.
}
};
+}
+
/// ConstructSSAForLoadSet - Given a set of loads specified by ValuesPerBlock,
/// construct SSA form, allowing us to eliminate LI. This returns the value
/// that should be used at LI's definition site.
Value *V = SSAUpdate.GetValueInMiddleOfBlock(LI->getParent());
// If new PHI nodes were created, notify alias analysis.
- if (isa<PointerType>(V->getType()))
+ if (V->getType()->isPointerTy())
for (unsigned i = 0, e = NewPHIs.size(); i != e; ++i)
AA->copyValue(LI, NewPHIs[i]);
return V;
}
-static bool isLifetimeStart(Instruction *Inst) {
- if (IntrinsicInst* II = dyn_cast<IntrinsicInst>(Inst))
+static bool isLifetimeStart(const Instruction *Inst) {
+ if (const IntrinsicInst* II = dyn_cast<IntrinsicInst>(Inst))
return II->getIntrinsicID() == Intrinsic::lifetime_start;
return false;
}
if (isa<PHINode>(V))
V->takeName(LI);
- if (isa<PointerType>(V->getType()))
+ if (V->getType()->isPointerTy())
MD->invalidateCachedPointerInfo(V);
+ VN.erase(LI);
toErase.push_back(LI);
- NumGVNLoad++;
+ ++NumGVNLoad;
return true;
}
while (TmpBB->getSinglePredecessor()) {
isSinglePred = true;
TmpBB = TmpBB->getSinglePredecessor();
- if (!TmpBB) // If haven't found any, bail now.
- return false;
if (TmpBB == LoadBB) // Infinite (unreachable) loop.
return false;
if (Blockers.count(TmpBB))
// at least one of the values is LI. Since this means that we won't be able
// to eliminate LI even if we insert uses in the other predecessors, we will
// end up increasing code size. Reject this by scanning for LI.
- for (unsigned i = 0, e = ValuesPerBlock.size(); i != e; ++i)
+ for (unsigned i = 0, e = ValuesPerBlock.size(); i != e; ++i) {
if (ValuesPerBlock[i].isSimpleValue() &&
- ValuesPerBlock[i].getSimpleValue() == LI)
- return false;
+ ValuesPerBlock[i].getSimpleValue() == LI) {
+ // Skip cases where LI is the only definition, even for EnableFullLoadPRE.
+ if (!EnableFullLoadPRE || e == 1)
+ return false;
+ }
+ }
// FIXME: It is extremely unclear what this loop is doing, other than
// artificially restricting loadpre.
return false;
}
- // Okay, we have some hope :). Check to see if the loaded value is fully
- // available in all but one predecessor.
- // FIXME: If we could restructure the CFG, we could make a common pred with
- // all the preds that don't have an available LI and insert a new load into
- // that one block.
- BasicBlock *UnavailablePred = 0;
-
+ // Check to see how many predecessors have the loaded value fully
+ // available.
+ DenseMap<BasicBlock*, Value*> PredLoads;
DenseMap<BasicBlock*, char> FullyAvailableBlocks;
for (unsigned i = 0, e = ValuesPerBlock.size(); i != e; ++i)
FullyAvailableBlocks[ValuesPerBlock[i].BB] = true;
for (unsigned i = 0, e = UnavailableBlocks.size(); i != e; ++i)
FullyAvailableBlocks[UnavailableBlocks[i]] = false;
+ SmallVector<std::pair<TerminatorInst*, unsigned>, 4> NeedToSplit;
for (pred_iterator PI = pred_begin(LoadBB), E = pred_end(LoadBB);
PI != E; ++PI) {
- if (IsValueFullyAvailableInBlock(*PI, FullyAvailableBlocks))
+ BasicBlock *Pred = *PI;
+ if (IsValueFullyAvailableInBlock(Pred, FullyAvailableBlocks)) {
continue;
+ }
+ PredLoads[Pred] = 0;
- // If this load is not available in multiple predecessors, reject it.
- if (UnavailablePred && UnavailablePred != *PI)
- return false;
- UnavailablePred = *PI;
+ if (Pred->getTerminator()->getNumSuccessors() != 1) {
+ if (isa<IndirectBrInst>(Pred->getTerminator())) {
+ DEBUG(dbgs() << "COULD NOT PRE LOAD BECAUSE OF INDBR CRITICAL EDGE '"
+ << Pred->getName() << "': " << *LI << '\n');
+ return false;
+ }
+ unsigned SuccNum = GetSuccessorNumber(Pred, LoadBB);
+ NeedToSplit.push_back(std::make_pair(Pred->getTerminator(), SuccNum));
+ }
+ }
+ if (!NeedToSplit.empty()) {
+ toSplit.append(NeedToSplit.begin(), NeedToSplit.end());
+ return false;
}
- assert(UnavailablePred != 0 &&
+ // Decide whether PRE is profitable for this load.
+ unsigned NumUnavailablePreds = PredLoads.size();
+ assert(NumUnavailablePreds != 0 &&
"Fully available value should be eliminated above!");
-
- // We don't currently handle critical edges :(
- if (UnavailablePred->getTerminator()->getNumSuccessors() != 1) {
- DEBUG(dbgs() << "COULD NOT PRE LOAD BECAUSE OF CRITICAL EDGE '"
- << UnavailablePred->getName() << "': " << *LI << '\n');
- return false;
+ if (!EnableFullLoadPRE) {
+ // If this load is unavailable in multiple predecessors, reject it.
+ // FIXME: If we could restructure the CFG, we could make a common pred with
+ // all the preds that don't have an available LI and insert a new load into
+ // that one block.
+ if (NumUnavailablePreds != 1)
+ return false;
}
-
- // Do PHI translation to get its value in the predecessor if necessary. The
- // returned pointer (if non-null) is guaranteed to dominate UnavailablePred.
- //
+
+ // Check if the load can safely be moved to all the unavailable predecessors.
+ bool CanDoPRE = true;
SmallVector<Instruction*, 8> NewInsts;
-
- // If all preds have a single successor, then we know it is safe to insert the
- // load on the pred (?!?), so we can insert code to materialize the pointer if
- // it is not available.
- PHITransAddr Address(LI->getOperand(0), TD);
- Value *LoadPtr = 0;
- if (allSingleSucc) {
- LoadPtr = Address.PHITranslateWithInsertion(LoadBB, UnavailablePred,
- *DT, NewInsts);
- } else {
- Address.PHITranslateValue(LoadBB, UnavailablePred);
- LoadPtr = Address.getAddr();
-
- // Make sure the value is live in the predecessor.
- if (Instruction *Inst = dyn_cast_or_null<Instruction>(LoadPtr))
- if (!DT->dominates(Inst->getParent(), UnavailablePred))
- LoadPtr = 0;
- }
+ for (DenseMap<BasicBlock*, Value*>::iterator I = PredLoads.begin(),
+ E = PredLoads.end(); I != E; ++I) {
+ BasicBlock *UnavailablePred = I->first;
+
+ // Do PHI translation to get its value in the predecessor if necessary. The
+ // returned pointer (if non-null) is guaranteed to dominate UnavailablePred.
+
+ // If all preds have a single successor, then we know it is safe to insert
+ // the load on the pred (?!?), so we can insert code to materialize the
+ // pointer if it is not available.
+ PHITransAddr Address(LI->getOperand(0), TD);
+ Value *LoadPtr = 0;
+ if (allSingleSucc) {
+ LoadPtr = Address.PHITranslateWithInsertion(LoadBB, UnavailablePred,
+ *DT, NewInsts);
+ } else {
+ Address.PHITranslateValue(LoadBB, UnavailablePred, DT);
+ LoadPtr = Address.getAddr();
+ }
- // If we couldn't find or insert a computation of this phi translated value,
- // we fail PRE.
- if (LoadPtr == 0) {
- assert(NewInsts.empty() && "Shouldn't insert insts on failure");
- DEBUG(dbgs() << "COULDN'T INSERT PHI TRANSLATED VALUE OF: "
- << *LI->getOperand(0) << "\n");
- return false;
- }
+ // If we couldn't find or insert a computation of this phi translated value,
+ // we fail PRE.
+ if (LoadPtr == 0) {
+ DEBUG(dbgs() << "COULDN'T INSERT PHI TRANSLATED VALUE OF: "
+ << *LI->getOperand(0) << "\n");
+ CanDoPRE = false;
+ break;
+ }
- // Assign value numbers to these new instructions.
- for (unsigned i = 0, e = NewInsts.size(); i != e; ++i) {
- // FIXME: We really _ought_ to insert these value numbers into their
- // parent's availability map. However, in doing so, we risk getting into
- // ordering issues. If a block hasn't been processed yet, we would be
- // marking a value as AVAIL-IN, which isn't what we intend.
- VN.lookup_or_add(NewInsts[i]);
+ // Make sure it is valid to move this load here. We have to watch out for:
+ // @1 = getelementptr (i8* p, ...
+ // test p and branch if == 0
+ // load @1
+ // It is valid to have the getelementptr before the test, even if p can be 0,
+ // as getelementptr only does address arithmetic.
+ // If we are not pushing the value through any multiple-successor blocks
+ // we do not have this case. Otherwise, check that the load is safe to
+ // put anywhere; this can be improved, but should be conservatively safe.
+ if (!allSingleSucc &&
+ // FIXME: REEVALUTE THIS.
+ !isSafeToLoadUnconditionally(LoadPtr,
+ UnavailablePred->getTerminator(),
+ LI->getAlignment(), TD)) {
+ CanDoPRE = false;
+ break;
+ }
+
+ I->second = LoadPtr;
}
-
- // Make sure it is valid to move this load here. We have to watch out for:
- // @1 = getelementptr (i8* p, ...
- // test p and branch if == 0
- // load @1
- // It is valid to have the getelementptr before the test, even if p can be 0,
- // as getelementptr only does address arithmetic.
- // If we are not pushing the value through any multiple-successor blocks
- // we do not have this case. Otherwise, check that the load is safe to
- // put anywhere; this can be improved, but should be conservatively safe.
- if (!allSingleSucc &&
- // FIXME: REEVALUTE THIS.
- !isSafeToLoadUnconditionally(LoadPtr, UnavailablePred->getTerminator())) {
- assert(NewInsts.empty() && "Should not have inserted instructions");
+
+ if (!CanDoPRE) {
+ while (!NewInsts.empty())
+ NewInsts.pop_back_val()->eraseFromParent();
return false;
}
dbgs() << "INSERTED " << NewInsts.size() << " INSTS: "
<< *NewInsts.back() << '\n');
- Value *NewLoad = new LoadInst(LoadPtr, LI->getName()+".pre", false,
- LI->getAlignment(),
- UnavailablePred->getTerminator());
+ // Assign value numbers to the new instructions.
+ for (unsigned i = 0, e = NewInsts.size(); i != e; ++i) {
+ // FIXME: We really _ought_ to insert these value numbers into their
+ // parent's availability map. However, in doing so, we risk getting into
+ // ordering issues. If a block hasn't been processed yet, we would be
+ // marking a value as AVAIL-IN, which isn't what we intend.
+ VN.lookup_or_add(NewInsts[i]);
+ }
+
+ for (DenseMap<BasicBlock*, Value*>::iterator I = PredLoads.begin(),
+ E = PredLoads.end(); I != E; ++I) {
+ BasicBlock *UnavailablePred = I->first;
+ Value *LoadPtr = I->second;
- // Add the newly created load.
- ValuesPerBlock.push_back(AvailableValueInBlock::get(UnavailablePred,NewLoad));
+ Value *NewLoad = new LoadInst(LoadPtr, LI->getName()+".pre", false,
+ LI->getAlignment(),
+ UnavailablePred->getTerminator());
+
+ // Add the newly created load.
+ ValuesPerBlock.push_back(AvailableValueInBlock::get(UnavailablePred,
+ NewLoad));
+ MD->invalidateCachedPointerInfo(LoadPtr);
+ DEBUG(dbgs() << "GVN INSERTED " << *NewLoad << '\n');
+ }
// Perform PHI construction.
Value *V = ConstructSSAForLoadSet(LI, ValuesPerBlock, TD, *DT,
LI->replaceAllUsesWith(V);
if (isa<PHINode>(V))
V->takeName(LI);
- if (isa<PointerType>(V->getType()))
+ if (V->getType()->isPointerTy())
MD->invalidateCachedPointerInfo(V);
+ VN.erase(LI);
toErase.push_back(LI);
- NumPRELoad++;
+ ++NumPRELoad;
return true;
}
// Replace the load!
L->replaceAllUsesWith(AvailVal);
- if (isa<PointerType>(AvailVal->getType()))
+ if (AvailVal->getType()->isPointerTy())
MD->invalidateCachedPointerInfo(AvailVal);
+ VN.erase(L);
toErase.push_back(L);
- NumGVNLoad++;
+ ++NumGVNLoad;
return true;
}
// Remove it!
L->replaceAllUsesWith(StoredVal);
- if (isa<PointerType>(StoredVal->getType()))
+ if (StoredVal->getType()->isPointerTy())
MD->invalidateCachedPointerInfo(StoredVal);
+ VN.erase(L);
toErase.push_back(L);
- NumGVNLoad++;
+ ++NumGVNLoad;
return true;
}
// Remove it!
L->replaceAllUsesWith(AvailableVal);
- if (isa<PointerType>(DepLI->getType()))
+ if (DepLI->getType()->isPointerTy())
MD->invalidateCachedPointerInfo(DepLI);
+ VN.erase(L);
toErase.push_back(L);
- NumGVNLoad++;
+ ++NumGVNLoad;
return true;
}
// intervening stores, for example.
if (isa<AllocaInst>(DepInst) || isMalloc(DepInst)) {
L->replaceAllUsesWith(UndefValue::get(L->getType()));
+ VN.erase(L);
toErase.push_back(L);
- NumGVNLoad++;
+ ++NumGVNLoad;
return true;
}
if (IntrinsicInst* II = dyn_cast<IntrinsicInst>(DepInst)) {
if (II->getIntrinsicID() == Intrinsic::lifetime_start) {
L->replaceAllUsesWith(UndefValue::get(L->getType()));
+ VN.erase(L);
toErase.push_back(L);
- NumGVNLoad++;
+ ++NumGVNLoad;
return true;
}
}
/// by inserting it into the appropriate sets
bool GVN::processInstruction(Instruction *I,
SmallVectorImpl<Instruction*> &toErase) {
+ // Ignore dbg info intrinsics.
+ if (isa<DbgInfoIntrinsic>(I))
+ return false;
+
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
bool Changed = processLoad(LI, toErase);
if (constVal) {
p->replaceAllUsesWith(constVal);
- if (MD && isa<PointerType>(constVal->getType()))
+ if (MD && constVal->getType()->isPointerTy())
MD->invalidateCachedPointerInfo(constVal);
VN.erase(p);
// Remove it!
VN.erase(I);
I->replaceAllUsesWith(repl);
- if (MD && isa<PointerType>(repl->getType()))
+ if (MD && repl->getType()->isPointerTy())
MD->invalidateCachedPointerInfo(repl);
toErase.push_back(I);
return true;
BasicBlock *BB = FI;
++FI;
bool removedBlock = MergeBlockIntoPredecessor(BB, this);
- if (removedBlock) NumGVNBlocks++;
+ if (removedBlock) ++NumGVNBlocks;
Changed |= removedBlock;
}
while (ShouldContinue) {
DEBUG(dbgs() << "GVN iteration: " << Iteration << "\n");
ShouldContinue = iterateOnFunction(F);
+ if (splitCriticalEdges())
+ ShouldContinue = true;
Changed |= ShouldContinue;
++Iteration;
}
/// control flow patterns and attempts to perform simple PRE at the join point.
bool GVN::performPRE(Function &F) {
bool Changed = false;
- SmallVector<std::pair<TerminatorInst*, unsigned>, 4> toSplit;
DenseMap<BasicBlock*, Value*> predMap;
for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()),
DE = df_end(&F.getEntryBlock()); DI != DE; ++DI) {
for (pred_iterator PI = pred_begin(CurrentBlock),
PE = pred_end(CurrentBlock); PI != PE; ++PI) {
+ BasicBlock *P = *PI;
// We're not interested in PRE where the block is its
- // own predecessor, on in blocks with predecessors
+ // own predecessor, or in blocks with predecessors
// that are not reachable.
- if (*PI == CurrentBlock) {
+ if (P == CurrentBlock) {
NumWithout = 2;
break;
- } else if (!localAvail.count(*PI)) {
+ } else if (!localAvail.count(P)) {
NumWithout = 2;
break;
}
DenseMap<uint32_t, Value*>::iterator predV =
- localAvail[*PI]->table.find(ValNo);
- if (predV == localAvail[*PI]->table.end()) {
- PREPred = *PI;
- NumWithout++;
+ localAvail[P]->table.find(ValNo);
+ if (predV == localAvail[P]->table.end()) {
+ PREPred = P;
+ ++NumWithout;
} else if (predV->second == CurInst) {
NumWithout = 2;
} else {
- predMap[*PI] = predV->second;
- NumWith++;
+ predMap[P] = predV->second;
+ ++NumWith;
}
}
// We can't do PRE safely on a critical edge, so instead we schedule
// the edge to be split and perform the PRE the next time we iterate
// on the function.
- unsigned SuccNum = 0;
- for (unsigned i = 0, e = PREPred->getTerminator()->getNumSuccessors();
- i != e; ++i)
- if (PREPred->getTerminator()->getSuccessor(i) == CurrentBlock) {
- SuccNum = i;
- break;
- }
-
+ unsigned SuccNum = GetSuccessorNumber(PREPred, CurrentBlock);
if (isCriticalEdge(PREPred->getTerminator(), SuccNum)) {
toSplit.push_back(std::make_pair(PREPred->getTerminator(), SuccNum));
continue;
}
- // Instantiate the expression the in predecessor that lacked it.
+ // Instantiate the expression in the predecessor that lacked it.
// Because we are going top-down through the block, all value numbers
// will be available in the predecessor by the time we need them. Any
- // that weren't original present will have been instantiated earlier
+ // that weren't originally present will have been instantiated earlier
// in this loop.
Instruction *PREInstr = CurInst->clone();
bool success = true;
PREInstr->setName(CurInst->getName() + ".pre");
predMap[PREPred] = PREInstr;
VN.add(PREInstr, ValNo);
- NumGVNPRE++;
+ ++NumGVNPRE;
// Update the availability map to include the new instruction.
localAvail[PREPred]->table.insert(std::make_pair(ValNo, PREInstr));
CurInst->getName() + ".pre-phi",
CurrentBlock->begin());
for (pred_iterator PI = pred_begin(CurrentBlock),
- PE = pred_end(CurrentBlock); PI != PE; ++PI)
- Phi->addIncoming(predMap[*PI], *PI);
+ PE = pred_end(CurrentBlock); PI != PE; ++PI) {
+ BasicBlock *P = *PI;
+ Phi->addIncoming(predMap[P], P);
+ }
VN.add(Phi, ValNo);
localAvail[CurrentBlock]->table[ValNo] = Phi;
CurInst->replaceAllUsesWith(Phi);
- if (MD && isa<PointerType>(Phi->getType()))
+ if (MD && Phi->getType()->isPointerTy())
MD->invalidateCachedPointerInfo(Phi);
VN.erase(CurInst);
}
}
- for (SmallVector<std::pair<TerminatorInst*, unsigned>, 4>::iterator
- I = toSplit.begin(), E = toSplit.end(); I != E; ++I)
- SplitCriticalEdge(I->first, I->second, this);
+ if (splitCriticalEdges())
+ Changed = true;
+
+ return Changed;
+}
- return Changed || toSplit.size();
+/// splitCriticalEdges - Split critical edges found during the previous
+/// iteration that may enable further optimization.
+bool GVN::splitCriticalEdges() {
+ if (toSplit.empty())
+ return false;
+ do {
+ std::pair<TerminatorInst*, unsigned> Edge = toSplit.pop_back_val();
+ SplitCriticalEdge(Edge.first, Edge.second, this);
+ } while (!toSplit.empty());
+ if (MD) MD->invalidateCachedPredecessors();
+ return true;
}
/// iterateOnFunction - Executes one iteration of GVN
projects / oota-llvm.git / blobdiff