#define DEBUG_TYPE "gvn"
#include "llvm/Transforms/Scalar.h"
-#include "llvm/BasicBlock.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
+#include "llvm/GlobalVariable.h"
#include "llvm/Function.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/LLVMContext.h"
#include "llvm/Operator.h"
-#include "llvm/Value.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/DepthFirstIterator.h"
-#include "llvm/ADT/PostOrderIterator.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Analysis/Loads.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/MemoryDependenceAnalysis.h"
+#include "llvm/Analysis/PHITransAddr.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/Utils/SSAUpdater.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DepthFirstIterator.h"
+#include "llvm/ADT/PostOrderIterator.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/Allocator.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/IRBuilder.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Transforms/Utils/SSAUpdater.h"
-#include <cstdio>
+#include <list>
using namespace llvm;
STATISTIC(NumGVNInstr, "Number of instructions deleted");
/// 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;
return false;
else if (function != other.function)
return false;
- else {
- if (varargs.size() != other.varargs.size())
- return false;
-
- for (size_t i = 0; i < varargs.size(); ++i)
- if (varargs[i] != other.varargs[i])
- return false;
-
- return true;
- }
+ else if (varargs != other.varargs)
+ return false;
+ return true;
}
- bool operator!=(const Expression &other) const {
+ /*bool operator!=(const Expression &other) const {
return !(*this == other);
- }
+ }*/
};
class ValueTable {
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);
Expression create_expression(CastInst* C);
Expression create_expression(GetElementPtrInst* G);
Expression create_expression(CallInst* C);
- Expression create_expression(Constant* C);
Expression create_expression(ExtractValueInst* C);
Expression create_expression(InsertValueInst* C);
void add(Value *V, uint32_t num);
void clear();
void erase(Value *v);
- unsigned size();
void setAliasAnalysis(AliasAnalysis* A) { AA = A; }
AliasAnalysis *getAliasAnalysis() const { return AA; }
void setMemDep(MemoryDependenceAnalysis* M) { MD = M; }
static bool isEqual(const Expression &LHS, const Expression &RHS) {
return LHS == RHS;
}
- static bool isPod() { return true; }
};
+
}
//===----------------------------------------------------------------------===//
// 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++;
// Check to see if we have a single dominating call instruction that is
// identical to C.
for (unsigned i = 0, e = deps.size(); i != e; ++i) {
- const MemoryDependenceAnalysis::NonLocalDepEntry *I = &deps[i];
+ const NonLocalDepEntry *I = &deps[i];
// Ignore non-local dependencies.
- if (I->second.isNonLocal())
+ if (I->getResult().isNonLocal())
continue;
// We don't handle non-depedencies. If we already have a call, reject
// instruction dependencies.
- if (I->second.isClobber() || cdep != 0) {
+ if (I->getResult().isClobber() || cdep != 0) {
cdep = 0;
break;
}
- CallInst *NonLocalDepCall = dyn_cast<CallInst>(I->second.getInst());
+ CallInst *NonLocalDepCall = dyn_cast<CallInst>(I->getResult().getInst());
// FIXME: All duplicated with non-local case.
- if (NonLocalDepCall && DT->properlyDominates(I->first, C->getParent())){
+ if (NonLocalDepCall && DT->properlyDominates(I->getBB(), C->getParent())){
cdep = NonLocalDepCall;
continue;
}
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) {
+ initializeGVNPass(*PassRegistry::getPassRegistry());
+ }
private:
- bool NoPRE;
bool NoLoads;
MemoryDependenceAnalysis *MD;
DominatorTree *DT;
+ const TargetData* TD;
ValueTable VN;
- DenseMap<BasicBlock*, ValueNumberScope*> localAvail;
+
+ /// NumberTable - A mapping from value numers to lists of Value*'s that
+ /// have that value number. Use lookupNumber to query it.
+ DenseMap<uint32_t, std::pair<Value*, void*> > NumberTable;
+ BumpPtrAllocator TableAllocator;
+
+ /// insert_table - Push a new Value to the NumberTable onto the list for
+ /// its value number.
+ void insert_table(uint32_t N, Value *V) {
+ std::pair<Value*, void*>& Curr = NumberTable[N];
+ if (!Curr.first) {
+ Curr.first = V;
+ return;
+ }
+
+ std::pair<Value*, void*>* Node =
+ TableAllocator.Allocate<std::pair<Value*, void*> >();
+ Node->first = V;
+ Node->second = Curr.second;
+ Curr.second = Node;
+ }
+
+ /// erase_table - Scan the list of values corresponding to a given value
+ /// number, and remove the given value if encountered.
+ void erase_table(uint32_t N, Value *V) {
+ std::pair<Value*, void*>* Prev = 0;
+ std::pair<Value*, void*>* Curr = &NumberTable[N];
+
+ while (Curr->first != V) {
+ Prev = Curr;
+ Curr = static_cast<std::pair<Value*, void*>*>(Curr->second);
+ }
+
+ if (Prev) {
+ Prev->second = Curr->second;
+ } else {
+ if (!Curr->second) {
+ Curr->first = 0;
+ } else {
+ std::pair<Value*, void*>* Next =
+ static_cast<std::pair<Value*, void*>*>(Curr->second);
+ Curr->first = Next->first;
+ Curr->second = Next->second;
+ }
+ }
+ }
+
+ // 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 {
bool processBlock(BasicBlock *BB);
void dump(DenseMap<uint32_t, Value*>& d);
bool iterateOnFunction(Function &F);
- Value *CollapsePhi(PHINode* p);
bool performPRE(Function& F);
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",
- "Global Value Numbering");
+INITIALIZE_PASS_BEGIN(GVN, "gvn", "Global Value Numbering", false, false)
+INITIALIZE_PASS_DEPENDENCY(MemoryDependenceAnalysis)
+INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
+INITIALIZE_PASS_END(GVN, "gvn", "Global Value Numbering", false, false)
void GVN::dump(DenseMap<uint32_t, Value*>& d) {
- printf("{\n");
+ errs() << "{\n";
for (DenseMap<uint32_t, Value*>::iterator I = d.begin(),
E = d.end(); I != E; ++I) {
- printf("%d\n", I->first);
+ errs() << I->first << "\n";
I->second->dump();
}
- printf("}\n");
-}
-
-static bool isSafeReplacement(PHINode* p, Instruction *inst) {
- if (!isa<PHINode>(inst))
- return true;
-
- for (Instruction::use_iterator UI = p->use_begin(), E = p->use_end();
- UI != E; ++UI)
- if (PHINode* use_phi = dyn_cast<PHINode>(UI))
- if (use_phi->getParent() == inst->getParent())
- return false;
-
- return true;
-}
-
-Value *GVN::CollapsePhi(PHINode *PN) {
- Value *ConstVal = PN->hasConstantValue(DT);
- if (!ConstVal) return 0;
-
- Instruction *Inst = dyn_cast<Instruction>(ConstVal);
- if (!Inst)
- return ConstVal;
-
- if (DT->dominates(Inst, PN))
- if (isSafeReplacement(PN, Inst))
- return Inst;
- return 0;
+ errs() << "}\n";
}
/// IsValueFullyAvailableInBlock - Return true if we can prove that the value
SmallVector<BasicBlock*, 32> BBWorklist;
BBWorklist.push_back(BB);
- while (!BBWorklist.empty()) {
+ do {
BasicBlock *Entry = BBWorklist.pop_back_val();
// Note that this sets blocks to 0 (unavailable) if they happen to not
// already be in FullyAvailableBlocks. This is safe.
for (succ_iterator I = succ_begin(Entry), E = succ_end(Entry); I != E; ++I)
BBWorklist.push_back(*I);
- }
+ } while (!BBWorklist.empty());
return false;
}
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.
return new BitCastInst(StoredVal, LoadedTy, "bitcast", InsertPt);
}
-/// GetBaseWithConstantOffset - Analyze the specified pointer to see if it can
-/// be expressed as a base pointer plus a constant offset. Return the base and
-/// offset to the caller.
-static Value *GetBaseWithConstantOffset(Value *Ptr, int64_t &Offset,
- const TargetData &TD) {
- Operator *PtrOp = dyn_cast<Operator>(Ptr);
- if (PtrOp == 0) return Ptr;
-
- // Just look through bitcasts.
- if (PtrOp->getOpcode() == Instruction::BitCast)
- return GetBaseWithConstantOffset(PtrOp->getOperand(0), Offset, TD);
-
- // If this is a GEP with constant indices, we can look through it.
- GEPOperator *GEP = dyn_cast<GEPOperator>(PtrOp);
- if (GEP == 0 || !GEP->hasAllConstantIndices()) return Ptr;
-
- gep_type_iterator GTI = gep_type_begin(GEP);
- for (User::op_iterator I = GEP->idx_begin(), E = GEP->idx_end(); I != E;
- ++I, ++GTI) {
- ConstantInt *OpC = cast<ConstantInt>(*I);
- if (OpC->isZero()) continue;
-
- // Handle a struct and array indices which add their offset to the pointer.
- if (const StructType *STy = dyn_cast<StructType>(*GTI)) {
- Offset += TD.getStructLayout(STy)->getElementOffset(OpC->getZExtValue());
- } else {
- uint64_t Size = TD.getTypeAllocSize(GTI.getIndexedType());
- Offset += OpC->getSExtValue()*Size;
- }
- }
-
- // Re-sign extend from the pointer size if needed to get overflow edge cases
- // right.
- unsigned PtrSize = TD.getPointerSizeInBits();
- if (PtrSize < 64)
- Offset = (Offset << (64-PtrSize)) >> (64-PtrSize);
-
- return GetBaseWithConstantOffset(GEP->getPointerOperand(), Offset, TD);
-}
-
-
/// AnalyzeLoadFromClobberingWrite - This function is called when we have a
/// memdep query of a load that ends up being a clobbering memory write (store,
/// memset, memcpy, memmove). This means that the write *may* provide bits used
/// Check this case to see if there is anything more we can do before we give
/// up. This returns -1 if we have to give up, or a byte number in the stored
/// value of the piece that feeds the load.
-static int AnalyzeLoadFromClobberingWrite(LoadInst *L, Value *WritePtr,
+static int AnalyzeLoadFromClobberingWrite(const Type *LoadTy, Value *LoadPtr,
+ Value *WritePtr,
uint64_t WriteSizeInBits,
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>(L->getType()) || isa<ArrayType>(L->getType()))
+ if (LoadTy->isStructTy() || LoadTy->isArrayTy())
return -1;
int64_t StoreOffset = 0, LoadOffset = 0;
- Value *StoreBase = GetBaseWithConstantOffset(WritePtr, StoreOffset, TD);
- Value *LoadBase =
- GetBaseWithConstantOffset(L->getPointerOperand(), LoadOffset, TD);
+ Value *StoreBase = GetPointerBaseWithConstantOffset(WritePtr, StoreOffset,TD);
+ Value *LoadBase = GetPointerBaseWithConstantOffset(LoadPtr, LoadOffset, TD);
if (StoreBase != LoadBase)
return -1;
// 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
- errs() << "STORE/LOAD DEP WITH COMMON POINTER MISSED:\n"
+ 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 = " << *L->getPointerOperand() << "\n"
- << "Load Offs = " << LoadOffset << " - " << *L << "\n\n";
- errs() << "'" << L->getParent()->getParent()->getName() << "'"
- << *L->getParent();
-#endif
- return -1;
+ << "Load Ptr = " << *LoadPtr << "\n";
+ abort();
}
+#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
// must have gotten confused.
- // FIXME: Investigate cases where this bails out, e.g. rdar://7238614. Then
- // remove this check, as it is duplicated with what we have below.
- uint64_t LoadSize = TD.getTypeSizeInBits(L->getType());
+ uint64_t LoadSize = TD.getTypeSizeInBits(LoadTy);
if ((WriteSizeInBits & 7) | (LoadSize & 7))
return -1;
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
- errs() << "STORE LOAD DEP WITH COMMON BASE:\n"
+ dbgs() << "STORE LOAD DEP WITH COMMON BASE:\n"
<< "Base = " << *StoreBase << "\n"
<< "Store Ptr = " << *WritePtr << "\n"
<< "Store Offs = " << StoreOffset << "\n"
- << "Load Ptr = " << *L->getPointerOperand() << "\n"
- << "Load Offs = " << LoadOffset << " - " << *L << "\n\n";
- errs() << "'" << L->getParent()->getParent()->getName() << "'"
- << *L->getParent();
+ << "Load Ptr = " << *LoadPtr << "\n";
+ abort();
#endif
return -1;
}
/// AnalyzeLoadFromClobberingStore - This function is called when we have a
/// memdep query of a load that ends up being a clobbering store.
-static int AnalyzeLoadFromClobberingStore(LoadInst *L, StoreInst *DepSI,
+static int AnalyzeLoadFromClobberingStore(const Type *LoadTy, Value *LoadPtr,
+ 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->getValueOperand()->getType()->isStructTy() ||
+ DepSI->getValueOperand()->getType()->isArrayTy())
return -1;
Value *StorePtr = DepSI->getPointerOperand();
- uint64_t StoreSize = TD.getTypeSizeInBits(StorePtr->getType());
- return AnalyzeLoadFromClobberingWrite(L, StorePtr, StoreSize, TD);
+ uint64_t StoreSize =TD.getTypeSizeInBits(DepSI->getValueOperand()->getType());
+ return AnalyzeLoadFromClobberingWrite(LoadTy, LoadPtr,
+ StorePtr, StoreSize, TD);
}
-static int AnalyzeLoadFromClobberingMemInst(LoadInst *L, MemIntrinsic *MI,
+static int AnalyzeLoadFromClobberingMemInst(const Type *LoadTy, Value *LoadPtr,
+ MemIntrinsic *MI,
const TargetData &TD) {
// If the mem operation is a non-constant size, we can't handle it.
ConstantInt *SizeCst = dyn_cast<ConstantInt>(MI->getLength());
// If this is memset, we just need to see if the offset is valid in the size
// of the memset..
if (MI->getIntrinsicID() == Intrinsic::memset)
- return AnalyzeLoadFromClobberingWrite(L, MI->getDest(), MemSizeInBits, TD);
+ return AnalyzeLoadFromClobberingWrite(LoadTy, LoadPtr, MI->getDest(),
+ MemSizeInBits, TD);
// If we have a memcpy/memmove, the only case we can handle is if this is a
// copy from constant memory. In that case, we can read directly from the
Constant *Src = dyn_cast<Constant>(MTI->getSource());
if (Src == 0) return -1;
- GlobalVariable *GV = dyn_cast<GlobalVariable>(Src->getUnderlyingObject());
+ GlobalVariable *GV = dyn_cast<GlobalVariable>(GetUnderlyingObject(Src));
if (GV == 0 || !GV->isConstant()) return -1;
// See if the access is within the bounds of the transfer.
- int Offset =
- AnalyzeLoadFromClobberingWrite(L, MI->getDest(), MemSizeInBits, TD);
+ int Offset = AnalyzeLoadFromClobberingWrite(LoadTy, LoadPtr,
+ MI->getDest(), MemSizeInBits, TD);
if (Offset == -1)
return Offset;
Constant *OffsetCst =
ConstantInt::get(Type::getInt64Ty(Src->getContext()), (unsigned)Offset);
Src = ConstantExpr::getGetElementPtr(Src, &OffsetCst, 1);
- Src = ConstantExpr::getBitCast(Src, PointerType::getUnqual(L->getType()));
+ Src = ConstantExpr::getBitCast(Src, PointerType::getUnqual(LoadTy));
if (ConstantFoldLoadFromConstPtr(Src, &TD))
return Offset;
return -1;
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()))
- SrcVal = new PtrToIntInst(SrcVal, TD.getIntPtrType(Ctx), "tmp", InsertPt);
- if (!isa<IntegerType>(SrcVal->getType()))
- SrcVal = new BitCastInst(SrcVal, IntegerType::get(Ctx, StoreSize*8),
- "tmp", InsertPt);
+ if (SrcVal->getType()->isPointerTy())
+ SrcVal = Builder.CreatePtrToInt(SrcVal, TD.getIntPtrType(Ctx), "tmp");
+ if (!SrcVal->getType()->isIntegerTy())
+ SrcVal = Builder.CreateBitCast(SrcVal, IntegerType::get(Ctx, StoreSize*8),
+ "tmp");
// Shift the bits to the least significant depending on endianness.
unsigned ShiftAmt;
ShiftAmt = (StoreSize-LoadSize-Offset)*8;
if (ShiftAmt)
- SrcVal = BinaryOperator::CreateLShr(SrcVal,
- ConstantInt::get(SrcVal->getType(), ShiftAmt), "tmp", InsertPt);
+ SrcVal = Builder.CreateLShr(SrcVal, ShiftAmt, "tmp");
if (LoadSize != StoreSize)
- SrcVal = new TruncInst(SrcVal, IntegerType::get(Ctx, LoadSize*8),
- "tmp", InsertPt);
+ SrcVal = Builder.CreateTrunc(SrcVal, IntegerType::get(Ctx, LoadSize*8),
+ "tmp");
return CoerceAvailableValueToLoadType(SrcVal, LoadTy, InsertPt, TD);
}
return ConstantFoldLoadFromConstPtr(Src, &TD);
}
-
+namespace {
struct AvailableValueInBlock {
/// BB - The basic block in question.
assert(!isSimpleValue() && "Wrong accessor");
return cast<MemIntrinsic>(Val.getPointer());
}
+
+ /// MaterializeAdjustedValue - Emit code into this block to adjust the value
+ /// defined here to the specified type. This handles various coercion cases.
+ Value *MaterializeAdjustedValue(const Type *LoadTy,
+ const TargetData *TD) const {
+ Value *Res;
+ if (isSimpleValue()) {
+ Res = getSimpleValue();
+ if (Res->getType() != LoadTy) {
+ assert(TD && "Need target data to handle type mismatch case");
+ Res = GetStoreValueForLoad(Res, Offset, LoadTy, BB->getTerminator(),
+ *TD);
+
+ DEBUG(errs() << "GVN COERCED NONLOCAL VAL:\nOffset: " << Offset << " "
+ << *getSimpleValue() << '\n'
+ << *Res << '\n' << "\n\n\n");
+ }
+ } else {
+ Res = GetMemInstValueForLoad(getMemIntrinValue(), Offset,
+ LoadTy, BB->getTerminator(), *TD);
+ DEBUG(errs() << "GVN COERCED NONLOCAL MEM INTRIN:\nOffset: " << Offset
+ << " " << *getMemIntrinValue() << '\n'
+ << *Res << '\n' << "\n\n\n");
+ }
+ return Res;
+ }
};
+}
+
/// 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.
static Value *ConstructSSAForLoadSet(LoadInst *LI,
SmallVectorImpl<AvailableValueInBlock> &ValuesPerBlock,
const TargetData *TD,
+ const DominatorTree &DT,
AliasAnalysis *AA) {
+ // Check for the fully redundant, dominating load case. In this case, we can
+ // just use the dominating value directly.
+ if (ValuesPerBlock.size() == 1 &&
+ DT.properlyDominates(ValuesPerBlock[0].BB, LI->getParent()))
+ return ValuesPerBlock[0].MaterializeAdjustedValue(LI->getType(), TD);
+
+ // Otherwise, we have to construct SSA form.
SmallVector<PHINode*, 8> NewPHIs;
SSAUpdater SSAUpdate(&NewPHIs);
- SSAUpdate.Initialize(LI);
+ SSAUpdate.Initialize(LI->getType(), LI->getName());
const Type *LoadTy = LI->getType();
if (SSAUpdate.HasValueForBlock(BB))
continue;
- unsigned Offset = AV.Offset;
-
- Value *AvailableVal;
- if (AV.isSimpleValue()) {
- AvailableVal = AV.getSimpleValue();
- if (AvailableVal->getType() != LoadTy) {
- assert(TD && "Need target data to handle type mismatch case");
- AvailableVal = GetStoreValueForLoad(AvailableVal, Offset, LoadTy,
- BB->getTerminator(), *TD);
-
- DEBUG(errs() << "GVN COERCED NONLOCAL VAL:\nOffset: " << Offset << " "
- << *AV.getSimpleValue() << '\n'
- << *AvailableVal << '\n' << "\n\n\n");
- }
- } else {
- AvailableVal = GetMemInstValueForLoad(AV.getMemIntrinValue(), Offset,
- LoadTy, BB->getTerminator(), *TD);
- DEBUG(errs() << "GVN COERCED NONLOCAL MEM INTRIN:\nOffset: " << Offset
- << " " << *AV.getMemIntrinValue() << '\n'
- << *AvailableVal << '\n' << "\n\n\n");
- }
- SSAUpdate.AddAvailableValue(BB, AvailableVal);
+ SSAUpdate.AddAvailableValue(BB, AV.MaterializeAdjustedValue(LoadTy, TD));
}
// Perform PHI construction.
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;
}
bool GVN::processNonLocalLoad(LoadInst *LI,
SmallVectorImpl<Instruction*> &toErase) {
// Find the non-local dependencies of the load.
- SmallVector<MemoryDependenceAnalysis::NonLocalDepEntry, 64> Deps;
- MD->getNonLocalPointerDependency(LI->getOperand(0), true, LI->getParent(),
- Deps);
- //DEBUG(errs() << "INVESTIGATING NONLOCAL LOAD: "
+ SmallVector<NonLocalDepResult, 64> Deps;
+ AliasAnalysis::Location Loc = VN.getAliasAnalysis()->getLocation(LI);
+ MD->getNonLocalPointerDependency(Loc, true, LI->getParent(), Deps);
+ //DEBUG(dbgs() << "INVESTIGATING NONLOCAL LOAD: "
// << Deps.size() << *LI << '\n');
// If we had to process more than one hundred blocks to find the
// If we had a phi translation failure, we'll have a single entry which is a
// clobber in the current block. Reject this early.
- if (Deps.size() == 1 && Deps[0].second.isClobber()) {
+ if (Deps.size() == 1 && Deps[0].getResult().isClobber()) {
DEBUG(
- errs() << "GVN: non-local load ";
- WriteAsOperand(errs(), LI);
- errs() << " is clobbered by " << *Deps[0].second.getInst() << '\n';
+ dbgs() << "GVN: non-local load ";
+ WriteAsOperand(dbgs(), LI);
+ dbgs() << " is clobbered by " << *Deps[0].getResult().getInst() << '\n';
);
return false;
}
SmallVector<AvailableValueInBlock, 16> ValuesPerBlock;
SmallVector<BasicBlock*, 16> UnavailableBlocks;
- const TargetData *TD = 0;
-
for (unsigned i = 0, e = Deps.size(); i != e; ++i) {
- BasicBlock *DepBB = Deps[i].first;
- MemDepResult DepInfo = Deps[i].second;
+ BasicBlock *DepBB = Deps[i].getBB();
+ MemDepResult DepInfo = Deps[i].getResult();
if (DepInfo.isClobber()) {
+ // The address being loaded in this non-local block may not be the same as
+ // the pointer operand of the load if PHI translation occurs. Make sure
+ // to consider the right address.
+ Value *Address = Deps[i].getAddress();
+
// If the dependence is to a store that writes to a superset of the bits
// read by the load, we can extract the bits we need for the load from the
// stored value.
if (StoreInst *DepSI = dyn_cast<StoreInst>(DepInfo.getInst())) {
- if (TD == 0)
- TD = getAnalysisIfAvailable<TargetData>();
- if (TD) {
- int Offset = AnalyzeLoadFromClobberingStore(LI, DepSI, *TD);
+ if (TD && Address) {
+ int Offset = AnalyzeLoadFromClobberingStore(LI->getType(), Address,
+ DepSI, *TD);
if (Offset != -1) {
ValuesPerBlock.push_back(AvailableValueInBlock::get(DepBB,
- DepSI->getOperand(0),
+ DepSI->getValueOperand(),
Offset));
continue;
}
// If the clobbering value is a memset/memcpy/memmove, see if we can
// forward a value on from it.
if (MemIntrinsic *DepMI = dyn_cast<MemIntrinsic>(DepInfo.getInst())) {
- if (TD == 0)
- TD = getAnalysisIfAvailable<TargetData>();
- if (TD) {
- int Offset = AnalyzeLoadFromClobberingMemInst(LI, DepMI, *TD);
+ if (TD && Address) {
+ int Offset = AnalyzeLoadFromClobberingMemInst(LI->getType(), Address,
+ DepMI, *TD);
if (Offset != -1) {
ValuesPerBlock.push_back(AvailableValueInBlock::getMI(DepBB, DepMI,
Offset));
if (StoreInst *S = dyn_cast<StoreInst>(DepInst)) {
// Reject loads and stores that are to the same address but are of
// different types if we have to.
- if (S->getOperand(0)->getType() != LI->getType()) {
- if (TD == 0)
- TD = getAnalysisIfAvailable<TargetData>();
-
+ if (S->getValueOperand()->getType() != LI->getType()) {
// If the stored value is larger or equal to the loaded value, we can
// reuse it.
- if (TD == 0 || !CanCoerceMustAliasedValueToLoad(S->getOperand(0),
+ if (TD == 0 || !CanCoerceMustAliasedValueToLoad(S->getValueOperand(),
LI->getType(), *TD)) {
UnavailableBlocks.push_back(DepBB);
continue;
}
ValuesPerBlock.push_back(AvailableValueInBlock::get(DepBB,
- S->getOperand(0)));
+ S->getValueOperand()));
continue;
}
if (LoadInst *LD = dyn_cast<LoadInst>(DepInst)) {
// If the types mismatch and we can't handle it, reject reuse of the load.
if (LD->getType() != LI->getType()) {
- if (TD == 0)
- TD = getAnalysisIfAvailable<TargetData>();
-
// If the stored value is larger or equal to the loaded value, we can
// reuse it.
if (TD == 0 || !CanCoerceMustAliasedValueToLoad(LD, LI->getType(),*TD)){
// load, then it is fully redundant and we can use PHI insertion to compute
// its value. Insert PHIs and remove the fully redundant value now.
if (UnavailableBlocks.empty()) {
- DEBUG(errs() << "GVN REMOVING NONLOCAL LOAD: " << *LI << '\n');
+ DEBUG(dbgs() << "GVN REMOVING NONLOCAL LOAD: " << *LI << '\n');
// Perform PHI construction.
- Value *V = ConstructSSAForLoadSet(LI, ValuesPerBlock, TD,
+ Value *V = ConstructSSAForLoadSet(LI, ValuesPerBlock, TD, *DT,
VN.getAliasAnalysis());
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);
- 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))
return false;
+
+ // If any of these blocks has more than one successor (i.e. if the edge we
+ // just traversed was critical), then there are other paths through this
+ // block along which the load may not be anticipated. Hoisting the load
+ // above this block would be adding the load to execution paths along
+ // which it was not previously executed.
if (TmpBB->getTerminator()->getNumSuccessors() != 1)
- allSingleSucc = false;
+ return false;
}
assert(TmpBB);
LoadBB = TmpBB;
- // If we have a repl set with LI itself in it, this means we have a loop where
- // 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)
- if (ValuesPerBlock[i].isSimpleValue() &&
- ValuesPerBlock[i].getSimpleValue() == LI)
- return false;
-
// FIXME: It is extremely unclear what this loop is doing, other than
// artificially restricting loadpre.
if (isSinglePred) {
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));
+ }
}
-
- assert(UnavailablePred != 0 &&
- "Fully available value should be eliminated above!");
-
- // We don't currently handle critical edges :(
- if (UnavailablePred->getTerminator()->getNumSuccessors() != 1) {
- DEBUG(errs() << "COULD NOT PRE LOAD BECAUSE OF CRITICAL EDGE '"
- << UnavailablePred->getName() << "': " << *LI << '\n');
+ if (!NeedToSplit.empty()) {
+ toSplit.append(NeedToSplit.begin(), NeedToSplit.end());
return false;
}
+
+ // Decide whether PRE is profitable for this load.
+ unsigned NumUnavailablePreds = PredLoads.size();
+ assert(NumUnavailablePreds != 0 &&
+ "Fully available value should be eliminated above!");
- // Do PHI translation to get its value in the predecessor if necessary. The
- // returned pointer (if non-null) is guaranteed to dominate UnavailablePred.
- //
- // FIXME: This may insert a computation, but we don't tell scalar GVN
- // optimization stuff about it. How do we do this?
+ // 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;
+
+ // Check if the load can safely be moved to all the unavailable predecessors.
+ bool CanDoPRE = true;
SmallVector<Instruction*, 8> NewInsts;
- Value *LoadPtr = 0;
-
- // 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.
- if (allSingleSucc) {
- LoadPtr = MD->InsertPHITranslatedPointer(LI->getOperand(0), LoadBB,
- UnavailablePred, TD, *DT,NewInsts);
- } else {
- LoadPtr = MD->GetAvailablePHITranslatedValue(LI->getOperand(0), LoadBB,
- UnavailablePred, TD, *DT);
- }
+ 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->getPointerOperand(), TD);
+ Value *LoadPtr = 0;
+ if (allSingleSucc) {
+ LoadPtr = Address.PHITranslateWithInsertion(LoadBB, UnavailablePred,
+ *DT, NewInsts);
+ } else {
+ Address.PHITranslateValue(LoadBB, UnavailablePred, DT);
+ LoadPtr = Address.getAddr();
+ }
- // Assign value numbers to these new instructions.
- for (SmallVector<Instruction*, 8>::iterator NI = NewInsts.begin(),
- NE = NewInsts.end(); NI != NE; ++NI) {
- // 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(*NI);
- }
-
- // If we couldn't find or insert a computation of this phi translated value,
- // we fail PRE.
- if (LoadPtr == 0) {
- DEBUG(errs() << "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->getPointerOperand() << "\n");
+ CanDoPRE = false;
+ break;
+ }
+
+ // 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;
}
// Okay, we can eliminate this load by inserting a reload in the predecessor
// and using PHI construction to get the value in the other predecessors, do
// it.
- DEBUG(errs() << "GVN REMOVING PRE LOAD: " << *LI << '\n');
+ DEBUG(dbgs() << "GVN REMOVING PRE LOAD: " << *LI << '\n');
DEBUG(if (!NewInsts.empty())
- errs() << "INSERTED " << NewInsts.size() << " INSTS: "
+ 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;
+
+ Instruction *NewLoad = new LoadInst(LoadPtr, LI->getName()+".pre", false,
+ LI->getAlignment(),
+ UnavailablePred->getTerminator());
+
+ // Transfer the old load's TBAA tag to the new load.
+ if (MDNode *Tag = LI->getMetadata(LLVMContext::MD_tbaa))
+ NewLoad->setMetadata(LLVMContext::MD_tbaa, Tag);
- // Add the newly created load.
- ValuesPerBlock.push_back(AvailableValueInBlock::get(UnavailablePred,NewLoad));
+ // 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,
+ Value *V = ConstructSSAForLoadSet(LI, ValuesPerBlock, TD, *DT,
VN.getAliasAnalysis());
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;
}
// access code.
Value *AvailVal = 0;
if (StoreInst *DepSI = dyn_cast<StoreInst>(Dep.getInst()))
- if (const TargetData *TD = getAnalysisIfAvailable<TargetData>()) {
- int Offset = AnalyzeLoadFromClobberingStore(L, DepSI, *TD);
+ if (TD) {
+ int Offset = AnalyzeLoadFromClobberingStore(L->getType(),
+ L->getPointerOperand(),
+ DepSI, *TD);
if (Offset != -1)
- AvailVal = GetStoreValueForLoad(DepSI->getOperand(0), Offset,
+ AvailVal = GetStoreValueForLoad(DepSI->getValueOperand(), Offset,
L->getType(), L, *TD);
}
// If the clobbering value is a memset/memcpy/memmove, see if we can forward
// a value on from it.
if (MemIntrinsic *DepMI = dyn_cast<MemIntrinsic>(Dep.getInst())) {
- if (const TargetData *TD = getAnalysisIfAvailable<TargetData>()) {
- int Offset = AnalyzeLoadFromClobberingMemInst(L, DepMI, *TD);
+ if (TD) {
+ int Offset = AnalyzeLoadFromClobberingMemInst(L->getType(),
+ L->getPointerOperand(),
+ DepMI, *TD);
if (Offset != -1)
AvailVal = GetMemInstValueForLoad(DepMI, Offset, L->getType(), L,*TD);
}
}
if (AvailVal) {
- DEBUG(errs() << "GVN COERCED INST:\n" << *Dep.getInst() << '\n'
+ DEBUG(dbgs() << "GVN COERCED INST:\n" << *Dep.getInst() << '\n'
<< *AvailVal << '\n' << *L << "\n\n\n");
// 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;
}
DEBUG(
// fast print dep, using operator<< on instruction would be too slow
- errs() << "GVN: load ";
- WriteAsOperand(errs(), L);
+ dbgs() << "GVN: load ";
+ WriteAsOperand(dbgs(), L);
Instruction *I = Dep.getInst();
- errs() << " is clobbered by " << *I << '\n';
+ dbgs() << " is clobbered by " << *I << '\n';
);
return false;
}
Instruction *DepInst = Dep.getInst();
if (StoreInst *DepSI = dyn_cast<StoreInst>(DepInst)) {
- Value *StoredVal = DepSI->getOperand(0);
+ Value *StoredVal = DepSI->getValueOperand();
// The store and load are to a must-aliased pointer, but they may not
// actually have the same type. See if we know how to reuse the stored
// value (depending on its type).
- const TargetData *TD = 0;
if (StoredVal->getType() != L->getType()) {
- if ((TD = getAnalysisIfAvailable<TargetData>())) {
+ if (TD) {
StoredVal = CoerceAvailableValueToLoadType(StoredVal, L->getType(),
L, *TD);
if (StoredVal == 0)
return false;
- DEBUG(errs() << "GVN COERCED STORE:\n" << *DepSI << '\n' << *StoredVal
+ DEBUG(dbgs() << "GVN COERCED STORE:\n" << *DepSI << '\n' << *StoredVal
<< '\n' << *L << "\n\n\n");
}
else
// 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;
}
// The loads are of a must-aliased pointer, but they may not actually have
// the same type. See if we know how to reuse the previously loaded value
// (depending on its type).
- const TargetData *TD = 0;
if (DepLI->getType() != L->getType()) {
- if ((TD = getAnalysisIfAvailable<TargetData>())) {
+ if (TD) {
AvailableVal = CoerceAvailableValueToLoadType(DepLI, L->getType(), L,*TD);
if (AvailableVal == 0)
return false;
- DEBUG(errs() << "GVN COERCED LOAD:\n" << *DepLI << "\n" << *AvailableVal
+ DEBUG(dbgs() << "GVN COERCED LOAD:\n" << *DepLI << "\n" << *AvailableVal
<< "\n" << *L << "\n\n\n");
}
else
// 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;
}
}
return false;
}
+// lookupNumber - In order to find a leader for a given value number at a
+// specific basic block, we first obtain the list of all Values for that number,
+// and then scan the list to find one whose block dominates the block in
+// question. This is fast because dominator tree queries consist of only
+// a few comparisons of DFS numbers.
Value *GVN::lookupNumber(BasicBlock *BB, uint32_t num) {
- DenseMap<BasicBlock*, ValueNumberScope*>::iterator I = localAvail.find(BB);
- if (I == localAvail.end())
- return 0;
-
- ValueNumberScope *Locals = I->second;
- while (Locals) {
- DenseMap<uint32_t, Value*>::iterator I = Locals->table.find(num);
- if (I != Locals->table.end())
- return I->second;
- Locals = Locals->parent;
+ std::pair<Value*, void*> Vals = NumberTable[num];
+ if (!Vals.first) return 0;
+ Instruction *Inst = dyn_cast<Instruction>(Vals.first);
+ if (!Inst) return Vals.first;
+ BasicBlock *Parent = Inst->getParent();
+ if (DT->dominates(Parent, BB))
+ return Inst;
+
+ std::pair<Value*, void*>* Next =
+ static_cast<std::pair<Value*, void*>*>(Vals.second);
+ while (Next) {
+ Instruction *CurrInst = dyn_cast<Instruction>(Next->first);
+ if (!CurrInst) return Next->first;
+
+ BasicBlock *Parent = CurrInst->getParent();
+ if (DT->dominates(Parent, BB))
+ return CurrInst;
+
+ Next = static_cast<std::pair<Value*, void*>*>(Next->second);
}
return 0;
/// 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 the instruction can be easily simplified then do so now in preference
+ // to value numbering it. Value numbering often exposes redundancies, for
+ // example if it determines that %y is equal to %x then the instruction
+ // "%z = and i32 %x, %y" becomes "%z = and i32 %x, %x" which we now simplify.
+ if (Value *V = SimplifyInstruction(I, TD, DT)) {
+ I->replaceAllUsesWith(V);
+ if (MD && V->getType()->isPointerTy())
+ MD->invalidateCachedPointerInfo(V);
+ VN.erase(I);
+ toErase.push_back(I);
+ return true;
+ }
+
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
bool Changed = processLoad(LI, toErase);
if (!Changed) {
unsigned Num = VN.lookup_or_add(LI);
- localAvail[I->getParent()]->table.insert(std::make_pair(Num, LI));
+ insert_table(Num, LI);
}
return Changed;
uint32_t NextNum = VN.getNextUnusedValueNumber();
unsigned Num = VN.lookup_or_add(I);
- if (BranchInst *BI = dyn_cast<BranchInst>(I)) {
- localAvail[I->getParent()]->table.insert(std::make_pair(Num, I));
-
- if (!BI->isConditional() || isa<Constant>(BI->getCondition()))
- return false;
-
- Value *BranchCond = BI->getCondition();
- uint32_t CondVN = VN.lookup_or_add(BranchCond);
-
- BasicBlock *TrueSucc = BI->getSuccessor(0);
- BasicBlock *FalseSucc = BI->getSuccessor(1);
-
- if (TrueSucc->getSinglePredecessor())
- localAvail[TrueSucc]->table[CondVN] =
- ConstantInt::getTrue(TrueSucc->getContext());
- if (FalseSucc->getSinglePredecessor())
- localAvail[FalseSucc]->table[CondVN] =
- ConstantInt::getFalse(TrueSucc->getContext());
-
- return false;
-
// Allocations are always uniquely numbered, so we can save time and memory
// by fast failing them.
- } else if (isa<AllocaInst>(I) || isa<TerminatorInst>(I)) {
- localAvail[I->getParent()]->table.insert(std::make_pair(Num, I));
+ if (isa<AllocaInst>(I) || isa<TerminatorInst>(I) || isa<PHINode>(I)) {
+ insert_table(Num, I);
return false;
}
- // Collapse PHI nodes
- if (PHINode* p = dyn_cast<PHINode>(I)) {
- Value *constVal = CollapsePhi(p);
-
- if (constVal) {
- p->replaceAllUsesWith(constVal);
- if (MD && isa<PointerType>(constVal->getType()))
- MD->invalidateCachedPointerInfo(constVal);
- VN.erase(p);
-
- toErase.push_back(p);
- } else {
- localAvail[I->getParent()]->table.insert(std::make_pair(Num, I));
- }
-
// If the number we were assigned was a brand new VN, then we don't
// need to do a lookup to see if the number already exists
// somewhere in the domtree: it can't!
- } else if (Num == NextNum) {
- localAvail[I->getParent()]->table.insert(std::make_pair(Num, I));
-
+ if (Num == NextNum) {
+ insert_table(Num, I);
+ return false;
+ }
+
// Perform fast-path value-number based elimination of values inherited from
// dominators.
- } else if (Value *repl = lookupNumber(I->getParent(), Num)) {
- // Remove it!
- VN.erase(I);
- I->replaceAllUsesWith(repl);
- if (MD && isa<PointerType>(repl->getType()))
- MD->invalidateCachedPointerInfo(repl);
- toErase.push_back(I);
- return true;
-
- } else {
- localAvail[I->getParent()]->table.insert(std::make_pair(Num, I));
+ Value *repl = lookupNumber(I->getParent(), Num);
+ if (repl == 0) {
+ // Failure, just remember this instance for future use.
+ insert_table(Num, I);
+ return false;
}
-
- return false;
+
+ // Remove it!
+ VN.erase(I);
+ I->replaceAllUsesWith(repl);
+ if (MD && repl->getType()->isPointerTy())
+ MD->invalidateCachedPointerInfo(repl);
+ toErase.push_back(I);
+ return true;
}
/// runOnFunction - This is the main transformation entry point for a function.
if (!NoLoads)
MD = &getAnalysis<MemoryDependenceAnalysis>();
DT = &getAnalysis<DominatorTree>();
+ TD = getAnalysisIfAvailable<TargetData>();
VN.setAliasAnalysis(&getAnalysis<AliasAnalysis>());
VN.setMemDep(MD);
VN.setDomTree(DT);
BasicBlock *BB = FI;
++FI;
bool removedBlock = MergeBlockIntoPredecessor(BB, this);
- if (removedBlock) NumGVNBlocks++;
+ if (removedBlock) ++NumGVNBlocks;
Changed |= removedBlock;
}
unsigned Iteration = 0;
while (ShouldContinue) {
- DEBUG(errs() << "GVN iteration: " << Iteration << "\n");
+ DEBUG(dbgs() << "GVN iteration: " << Iteration << "\n");
ShouldContinue = iterateOnFunction(F);
+ if (splitCriticalEdges())
+ ShouldContinue = true;
Changed |= ShouldContinue;
++Iteration;
}
for (SmallVector<Instruction*, 4>::iterator I = toErase.begin(),
E = toErase.end(); I != E; ++I) {
- DEBUG(errs() << "GVN removed: " << **I << '\n');
+ DEBUG(dbgs() << "GVN removed: " << **I << '\n');
if (MD) MD->removeInstruction(*I);
(*I)->eraseFromParent();
DEBUG(verifyRemoved(*I));
/// 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) {
CurInst->mayReadFromMemory() || CurInst->mayHaveSideEffects() ||
isa<DbgInfoIntrinsic>(CurInst))
continue;
+
+ // We don't currently value number ANY inline asm calls.
+ if (CallInst *CallI = dyn_cast<CallInst>(CurInst))
+ if (CallI->isInlineAsm())
+ continue;
uint32_t ValNo = VN.lookup(CurInst);
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 (!DT->dominates(&F.getEntryBlock(), P)) {
NumWithout = 2;
break;
}
- DenseMap<uint32_t, Value*>::iterator predV =
- localAvail[*PI]->table.find(ValNo);
- if (predV == localAvail[*PI]->table.end()) {
- PREPred = *PI;
- NumWithout++;
- } else if (predV->second == CurInst) {
+ Value* predV = lookupNumber(P, ValNo);
+ if (predV == 0) {
+ PREPred = P;
+ ++NumWithout;
+ } else if (predV == CurInst) {
NumWithout = 2;
} else {
- predMap[*PI] = predV->second;
- NumWith++;
+ predMap[P] = predV;
+ ++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));
+ insert_table(ValNo, PREInstr);
// Create a PHI to make the value available in this block.
PHINode* Phi = PHINode::Create(CurInst->getType(),
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;
+ insert_table(ValNo, Phi);
CurInst->replaceAllUsesWith(Phi);
- if (MD && isa<PointerType>(Phi->getType()))
+ if (MD && Phi->getType()->isPointerTy())
MD->invalidateCachedPointerInfo(Phi);
VN.erase(CurInst);
+ erase_table(ValNo, CurInst);
- DEBUG(errs() << "GVN PRE removed: " << *CurInst << '\n');
+ DEBUG(dbgs() << "GVN PRE removed: " << *CurInst << '\n');
if (MD) MD->removeInstruction(CurInst);
CurInst->eraseFromParent();
DEBUG(verifyRemoved(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
bool GVN::iterateOnFunction(Function &F) {
cleanupGlobalSets();
-
- for (df_iterator<DomTreeNode*> DI = df_begin(DT->getRootNode()),
- DE = df_end(DT->getRootNode()); DI != DE; ++DI) {
- if (DI->getIDom())
- localAvail[DI->getBlock()] =
- new ValueNumberScope(localAvail[DI->getIDom()->getBlock()]);
- else
- localAvail[DI->getBlock()] = new ValueNumberScope(0);
- }
-
+
// Top-down walk of the dominator tree
bool Changed = false;
#if 0
void GVN::cleanupGlobalSets() {
VN.clear();
-
- for (DenseMap<BasicBlock*, ValueNumberScope*>::iterator
- I = localAvail.begin(), E = localAvail.end(); I != E; ++I)
- delete I->second;
- localAvail.clear();
+ NumberTable.clear();
+ TableAllocator.Reset();
}
/// verifyRemoved - Verify that the specified instruction does not occur in our
// Walk through the value number scope to make sure the instruction isn't
// ferreted away in it.
- for (DenseMap<BasicBlock*, ValueNumberScope*>::const_iterator
- I = localAvail.begin(), E = localAvail.end(); I != E; ++I) {
- const ValueNumberScope *VNS = I->second;
-
- while (VNS) {
- for (DenseMap<uint32_t, Value*>::const_iterator
- II = VNS->table.begin(), IE = VNS->table.end(); II != IE; ++II) {
- assert(II->second != Inst && "Inst still in value numbering scope!");
- }
-
- VNS = VNS->parent;
+ for (DenseMap<uint32_t, std::pair<Value*, void*> >::const_iterator
+ I = NumberTable.begin(), E = NumberTable.end(); I != E; ++I) {
+ std::pair<Value*, void*> const * Node = &I->second;
+ assert(Node->first != Inst && "Inst still in value numbering scope!");
+
+ while (Node->second) {
+ Node = static_cast<std::pair<Value*, void*>*>(Node->second);
+ assert(Node->first != Inst && "Inst still in value numbering scope!");
}
}
}
projects / oota-llvm.git / blobdiff