#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/MemoryBuiltins.h"
+#include "llvm/Analysis/PHITransAddr.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/PredIteratorCache.h"
const Type *EltTy = cast<PointerType>(Pointer->getType())->getElementType();
uint64_t PointeeSize = AA->getTypeStoreSize(EltTy);
+ PHITransAddr Address(Pointer, TD);
+
// This is the set of blocks we've inspected, and the pointer we consider in
// each block. Because of critical edges, we currently bail out if querying
// a block with multiple different pointers. This can happen during PHI
// translation.
DenseMap<BasicBlock*, Value*> Visited;
- if (!getNonLocalPointerDepFromBB(Pointer, PointeeSize, isLoad, FromBB,
+ if (!getNonLocalPointerDepFromBB(Address, PointeeSize, isLoad, FromBB,
Result, Visited, true))
return;
Result.clear();
}
}
-/// isPHITranslatable - Return true if the specified computation is derived from
-/// a PHI node in the current block and if it is simple enough for us to handle.
-static bool isPHITranslatable(Instruction *Inst) {
- if (isa<PHINode>(Inst))
- return true;
-
- // We can handle bitcast of a PHI, but the PHI needs to be in the same block
- // as the bitcast.
- if (BitCastInst *BC = dyn_cast<BitCastInst>(Inst)) {
- Instruction *OpI = dyn_cast<Instruction>(BC->getOperand(0));
- if (OpI == 0 || OpI->getParent() != Inst->getParent())
- return true;
- return isPHITranslatable(OpI);
- }
-
- // We can translate a GEP if all of its operands defined in this block are phi
- // translatable.
- if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
- for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) {
- Instruction *OpI = dyn_cast<Instruction>(GEP->getOperand(i));
- if (OpI == 0 || OpI->getParent() != Inst->getParent())
- continue;
-
- if (!isPHITranslatable(OpI))
- return false;
- }
- return true;
- }
-
- if (Inst->getOpcode() == Instruction::Add &&
- isa<ConstantInt>(Inst->getOperand(1))) {
- Instruction *OpI = dyn_cast<Instruction>(Inst->getOperand(0));
- if (OpI == 0 || OpI->getParent() != Inst->getParent())
- return true;
- return isPHITranslatable(OpI);
- }
-
- // cerr << "MEMDEP: Could not PHI translate: " << *Pointer;
- // if (isa<BitCastInst>(PtrInst) || isa<GetElementPtrInst>(PtrInst))
- // cerr << "OP:\t\t\t\t" << *PtrInst->getOperand(0);
-
- return false;
-}
-
-/// GetPHITranslatedValue - Given a computation that satisfied the
-/// isPHITranslatable predicate, see if we can translate the computation into
-/// the specified predecessor block. If so, return that value.
-Value *MemoryDependenceAnalysis::
-GetPHITranslatedValue(Value *InVal, BasicBlock *CurBB, BasicBlock *Pred,
- const TargetData *TD) const {
- // If the input value is not an instruction, or if it is not defined in CurBB,
- // then we don't need to phi translate it.
- Instruction *Inst = dyn_cast<Instruction>(InVal);
- if (Inst == 0 || Inst->getParent() != CurBB)
- return InVal;
-
- if (PHINode *PN = dyn_cast<PHINode>(Inst))
- return PN->getIncomingValueForBlock(Pred);
-
- // Handle bitcast of PHI.
- if (BitCastInst *BC = dyn_cast<BitCastInst>(Inst)) {
- // PHI translate the input operand.
- Value *PHIIn = GetPHITranslatedValue(BC->getOperand(0), CurBB, Pred, TD);
- if (PHIIn == 0) return 0;
-
- // Constants are trivial to phi translate.
- if (Constant *C = dyn_cast<Constant>(PHIIn))
- return ConstantExpr::getBitCast(C, BC->getType());
-
- // Otherwise we have to see if a bitcasted version of the incoming pointer
- // is available. If so, we can use it, otherwise we have to fail.
- for (Value::use_iterator UI = PHIIn->use_begin(), E = PHIIn->use_end();
- UI != E; ++UI) {
- if (BitCastInst *BCI = dyn_cast<BitCastInst>(*UI))
- if (BCI->getType() == BC->getType())
- return BCI;
- }
- return 0;
- }
-
- // Handle getelementptr with at least one PHI translatable operand.
- if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
- SmallVector<Value*, 8> GEPOps;
- BasicBlock *CurBB = GEP->getParent();
- for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) {
- Value *GEPOp = GEP->getOperand(i);
- // No PHI translation is needed of operands whose values are live in to
- // the predecessor block.
- if (!isa<Instruction>(GEPOp) ||
- cast<Instruction>(GEPOp)->getParent() != CurBB) {
- GEPOps.push_back(GEPOp);
- continue;
- }
-
- // If the operand is a phi node, do phi translation.
- Value *InOp = GetPHITranslatedValue(GEPOp, CurBB, Pred, TD);
- if (InOp == 0) return 0;
-
- GEPOps.push_back(InOp);
- }
-
- // Simplify the GEP to handle 'gep x, 0' -> x etc.
- if (Value *V = SimplifyGEPInst(&GEPOps[0], GEPOps.size(), TD))
- return V;
-
- // Scan to see if we have this GEP available.
- Value *APHIOp = GEPOps[0];
- for (Value::use_iterator UI = APHIOp->use_begin(), E = APHIOp->use_end();
- UI != E; ++UI) {
- if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(*UI))
- if (GEPI->getType() == GEP->getType() &&
- GEPI->getNumOperands() == GEPOps.size() &&
- GEPI->getParent()->getParent() == CurBB->getParent()) {
- bool Mismatch = false;
- for (unsigned i = 0, e = GEPOps.size(); i != e; ++i)
- if (GEPI->getOperand(i) != GEPOps[i]) {
- Mismatch = true;
- break;
- }
- if (!Mismatch)
- return GEPI;
- }
- }
- return 0;
- }
-
- // Handle add with a constant RHS.
- if (Inst->getOpcode() == Instruction::Add &&
- isa<ConstantInt>(Inst->getOperand(1))) {
- // PHI translate the LHS.
- Value *LHS;
- Constant *RHS = cast<ConstantInt>(Inst->getOperand(1));
- Instruction *OpI = dyn_cast<Instruction>(Inst->getOperand(0));
- bool isNSW = cast<BinaryOperator>(Inst)->hasNoSignedWrap();
- bool isNUW = cast<BinaryOperator>(Inst)->hasNoUnsignedWrap();
-
- if (OpI == 0 || OpI->getParent() != Inst->getParent())
- LHS = Inst->getOperand(0);
- else {
- LHS = GetPHITranslatedValue(Inst->getOperand(0), CurBB, Pred, TD);
- if (LHS == 0)
- return 0;
- }
-
- // If the PHI translated LHS is an add of a constant, fold the immediates.
- if (BinaryOperator *BOp = dyn_cast<BinaryOperator>(LHS))
- if (BOp->getOpcode() == Instruction::Add)
- if (ConstantInt *CI = dyn_cast<ConstantInt>(BOp->getOperand(1))) {
- LHS = BOp->getOperand(0);
- RHS = ConstantExpr::getAdd(RHS, CI);
- isNSW = isNUW = false;
- }
-
- // See if the add simplifies away.
- if (Value *Res = SimplifyAddInst(LHS, RHS, isNSW, isNUW, TD))
- return Res;
-
- // Otherwise, see if we have this add available somewhere.
- for (Value::use_iterator UI = LHS->use_begin(), E = LHS->use_end();
- UI != E; ++UI) {
- if (BinaryOperator *BO = dyn_cast<BinaryOperator>(*UI))
- if (BO->getOperand(0) == LHS && BO->getOperand(1) == RHS &&
- BO->getParent()->getParent() == CurBB->getParent())
- return BO;
- }
-
- return 0;
- }
-
- return 0;
-}
-
-/// GetAvailablePHITranslatePointer - Return the value computed by
-/// PHITranslatePointer if it dominates PredBB, otherwise return null.
-Value *MemoryDependenceAnalysis::
-GetAvailablePHITranslatedValue(Value *V,
- BasicBlock *CurBB, BasicBlock *PredBB,
- const TargetData *TD,
- const DominatorTree &DT) const {
- // See if PHI translation succeeds.
- V = GetPHITranslatedValue(V, CurBB, PredBB, TD);
- if (V == 0) return 0;
-
- // Make sure the value is live in the predecessor.
- if (Instruction *Inst = dyn_cast_or_null<Instruction>(V))
- if (!DT.dominates(Inst->getParent(), PredBB))
- return 0;
- return V;
-}
-
-
-/// InsertPHITranslatedPointer - Insert a computation of the PHI translated
-/// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
-/// block. All newly created instructions are added to the NewInsts list.
-///
-Value *MemoryDependenceAnalysis::
-InsertPHITranslatedPointer(Value *InVal, BasicBlock *CurBB,
- BasicBlock *PredBB, const TargetData *TD,
- const DominatorTree &DT,
- SmallVectorImpl<Instruction*> &NewInsts) const {
- // See if we have a version of this value already available and dominating
- // PredBB. If so, there is no need to insert a new copy.
- if (Value *Res = GetAvailablePHITranslatedValue(InVal, CurBB, PredBB, TD, DT))
- return Res;
-
- // If we don't have an available version of this value, it must be an
- // instruction.
- Instruction *Inst = cast<Instruction>(InVal);
-
- // Handle bitcast of PHI translatable value.
- if (BitCastInst *BC = dyn_cast<BitCastInst>(Inst)) {
- Value *OpVal = InsertPHITranslatedPointer(BC->getOperand(0),
- CurBB, PredBB, TD, DT, NewInsts);
- if (OpVal == 0) return 0;
-
- // Otherwise insert a bitcast at the end of PredBB.
- BitCastInst *New = new BitCastInst(OpVal, InVal->getType(),
- InVal->getName()+".phi.trans.insert",
- PredBB->getTerminator());
- NewInsts.push_back(New);
- return New;
- }
-
- // Handle getelementptr with at least one PHI operand.
- if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
- SmallVector<Value*, 8> GEPOps;
- BasicBlock *CurBB = GEP->getParent();
- for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) {
- Value *OpVal = InsertPHITranslatedPointer(GEP->getOperand(i),
- CurBB, PredBB, TD, DT, NewInsts);
- if (OpVal == 0) return 0;
- GEPOps.push_back(OpVal);
- }
-
- GetElementPtrInst *Result =
- GetElementPtrInst::Create(GEPOps[0], GEPOps.begin()+1, GEPOps.end(),
- InVal->getName()+".phi.trans.insert",
- PredBB->getTerminator());
- Result->setIsInBounds(GEP->isInBounds());
- NewInsts.push_back(Result);
- return Result;
- }
-
-#if 0
- // FIXME: This code works, but it is unclear that we actually want to insert
- // a big chain of computation in order to make a value available in a block.
- // This needs to be evaluated carefully to consider its cost trade offs.
-
- // Handle add with a constant RHS.
- if (Inst->getOpcode() == Instruction::Add &&
- isa<ConstantInt>(Inst->getOperand(1))) {
- // PHI translate the LHS.
- Value *OpVal = InsertPHITranslatedPointer(Inst->getOperand(0),
- CurBB, PredBB, TD, DT, NewInsts);
- if (OpVal == 0) return 0;
-
- BinaryOperator *Res = BinaryOperator::CreateAdd(OpVal, Inst->getOperand(1),
- InVal->getName()+".phi.trans.insert",
- PredBB->getTerminator());
- Res->setHasNoSignedWrap(cast<BinaryOperator>(Inst)->hasNoSignedWrap());
- Res->setHasNoUnsignedWrap(cast<BinaryOperator>(Inst)->hasNoUnsignedWrap());
- NewInsts.push_back(Res);
- return Res;
- }
-#endif
-
- return 0;
-}
-
/// getNonLocalPointerDepFromBB - Perform a dependency query based on
/// pointer/pointeesize starting at the end of StartBB. Add any clobber/def
/// results to the results vector and keep track of which blocks are visited in
/// not compute dependence information for some reason. This should be treated
/// as a clobber dependence on the first instruction in the predecessor block.
bool MemoryDependenceAnalysis::
-getNonLocalPointerDepFromBB(Value *Pointer, uint64_t PointeeSize,
+getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, uint64_t PointeeSize,
bool isLoad, BasicBlock *StartBB,
SmallVectorImpl<NonLocalDepEntry> &Result,
DenseMap<BasicBlock*, Value*> &Visited,
bool SkipFirstBlock) {
// Look up the cached info for Pointer.
- ValueIsLoadPair CacheKey(Pointer, isLoad);
+ ValueIsLoadPair CacheKey(Pointer.getAddr(), isLoad);
std::pair<BBSkipFirstBlockPair, NonLocalDepInfo> *CacheInfo =
&NonLocalPointerDeps[CacheKey];
for (NonLocalDepInfo::iterator I = Cache->begin(), E = Cache->end();
I != E; ++I) {
DenseMap<BasicBlock*, Value*>::iterator VI = Visited.find(I->first);
- if (VI == Visited.end() || VI->second == Pointer) continue;
+ if (VI == Visited.end() || VI->second == Pointer.getAddr())
+ continue;
// We have a pointer mismatch in a block. Just return clobber, saying
// that something was clobbered in this result. We could also do a
for (NonLocalDepInfo::iterator I = Cache->begin(), E = Cache->end();
I != E; ++I) {
- Visited.insert(std::make_pair(I->first, Pointer));
+ Visited.insert(std::make_pair(I->first, Pointer.getAddr()));
if (!I->second.isNonLocal())
Result.push_back(*I);
}
// Get the dependency info for Pointer in BB. If we have cached
// information, we will use it, otherwise we compute it.
DEBUG(AssertSorted(*Cache, NumSortedEntries));
- MemDepResult Dep = GetNonLocalInfoForBlock(Pointer, PointeeSize, isLoad,
- BB, Cache, NumSortedEntries);
+ MemDepResult Dep = GetNonLocalInfoForBlock(Pointer.getAddr(), PointeeSize,
+ isLoad, BB, Cache,
+ NumSortedEntries);
// If we got a Def or Clobber, add this to the list of results.
if (!Dep.isNonLocal()) {
// If 'Pointer' is an instruction defined in this block, then we need to do
// phi translation to change it into a value live in the predecessor block.
- // If phi translation fails, then we can't continue dependence analysis.
- Instruction *PtrInst = dyn_cast<Instruction>(Pointer);
- bool NeedsPHITranslation = PtrInst && PtrInst->getParent() == BB;
-
- // If no PHI translation is needed, just add all the predecessors of this
- // block to scan them as well.
- if (!NeedsPHITranslation) {
+ // If not, we just add the predecessors to the worklist and scan them with
+ // the same Pointer.
+ if (!Pointer.NeedsPHITranslationFromBlock(BB)) {
SkipFirstBlock = false;
for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI) {
// Verify that we haven't looked at this block yet.
std::pair<DenseMap<BasicBlock*,Value*>::iterator, bool>
- InsertRes = Visited.insert(std::make_pair(*PI, Pointer));
+ InsertRes = Visited.insert(std::make_pair(*PI, Pointer.getAddr()));
if (InsertRes.second) {
// First time we've looked at *PI.
Worklist.push_back(*PI);
// If we have seen this block before, but it was with a different
// pointer then we have a phi translation failure and we have to treat
// this as a clobber.
- if (InsertRes.first->second != Pointer)
+ if (InsertRes.first->second != Pointer.getAddr())
goto PredTranslationFailure;
}
continue;
}
- // If we do need to do phi translation, then there are a bunch of different
- // cases, because we have to find a Value* live in the predecessor block. We
- // know that PtrInst is defined in this block at least.
-
+ // We do need to do phi translation, if we know ahead of time we can't phi
+ // translate this value, don't even try.
+ if (!Pointer.IsPotentiallyPHITranslatable())
+ goto PredTranslationFailure;
+
// We may have added values to the cache list before this PHI translation.
// If so, we haven't done anything to ensure that the cache remains sorted.
// Sort it now (if needed) so that recursive invocations of
SortNonLocalDepInfoCache(*Cache, NumSortedEntries);
NumSortedEntries = Cache->size();
}
-
- // If this is a computation derived from a PHI node, use the suitably
- // translated incoming values for each pred as the phi translated version.
- if (!isPHITranslatable(PtrInst))
- goto PredTranslationFailure;
-
Cache = 0;
-
+
for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI) {
BasicBlock *Pred = *PI;
- // Get the PHI translated pointer in this predecessor. This can fail and
- // return null if not translatable.
- Value *PredPtr = GetPHITranslatedValue(PtrInst, BB, Pred, TD);
+
+ // Get the PHI translated pointer in this predecessor. This can fail if
+ // not translatable, in which case the getAddr() returns null.
+ PHITransAddr PredPointer(Pointer);
+ PredPointer.PHITranslateValue(BB, Pred);
+
+ Value *PredPtrVal = PredPointer.getAddr();
// Check to see if we have already visited this pred block with another
// pointer. If so, we can't do this lookup. This failure can occur
// the successor translates to a pointer value different than the
// pointer the block was first analyzed with.
std::pair<DenseMap<BasicBlock*,Value*>::iterator, bool>
- InsertRes = Visited.insert(std::make_pair(Pred, PredPtr));
+ InsertRes = Visited.insert(std::make_pair(Pred, PredPtrVal));
if (!InsertRes.second) {
// If the predecessor was visited with PredPtr, then we already did
// the analysis and can ignore it.
- if (InsertRes.first->second == PredPtr)
+ if (InsertRes.first->second == PredPtrVal)
continue;
// Otherwise, the block was previously analyzed with a different
// predecessor, then we have to assume that the pointer is clobbered in
// that predecessor. We can still do PRE of the load, which would insert
// a computation of the pointer in this predecessor.
- if (PredPtr == 0) {
+ if (PredPtrVal == 0) {
// Add the entry to the Result list.
NonLocalDepEntry Entry(Pred,
MemDepResult::getClobber(Pred->getTerminator()));
// If we have a problem phi translating, fall through to the code below
// to handle the failure condition.
- if (getNonLocalPointerDepFromBB(PredPtr, PointeeSize, isLoad, Pred,
+ if (getNonLocalPointerDepFromBB(PredPointer, PointeeSize, isLoad, Pred,
Result, Visited))
goto PredTranslationFailure;
}
projects / oota-llvm.git / commitdiff