X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FPHITransAddr.cpp;h=bfe86425119be24c0a87d9414c16e8ebe019dabe;hb=93710f07f02b3961556d2344e1baab1f53e4b45e;hp=bdaaac1eaa1f738e2bd4161638ed47b79502d675;hpb=9a8641201b2db8427be2a6531c043f384562c081;p=oota-llvm.git diff --git a/lib/Analysis/PHITransAddr.cpp b/lib/Analysis/PHITransAddr.cpp index bdaaac1eaa1..bfe86425119 100644 --- a/lib/Analysis/PHITransAddr.cpp +++ b/lib/Analysis/PHITransAddr.cpp @@ -12,10 +12,103 @@ //===----------------------------------------------------------------------===// #include "llvm/Analysis/PHITransAddr.h" -#include "llvm/Analysis/Dominators.h" #include "llvm/Analysis/InstructionSimplify.h" +#include "llvm/Analysis/ValueTracking.h" +#include "llvm/IR/Constants.h" +#include "llvm/IR/Dominators.h" +#include "llvm/IR/Instructions.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/raw_ostream.h" using namespace llvm; +static bool CanPHITrans(Instruction *Inst) { + if (isa(Inst) || + isa(Inst)) + return true; + + if (isa(Inst) && + isSafeToSpeculativelyExecute(Inst)) + return true; + + if (Inst->getOpcode() == Instruction::Add && + isa(Inst->getOperand(1))) + return true; + + // cerr << "MEMDEP: Could not PHI translate: " << *Pointer; + // if (isa(PtrInst) || isa(PtrInst)) + // cerr << "OP:\t\t\t\t" << *PtrInst->getOperand(0); + return false; +} + +#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) +void PHITransAddr::dump() const { + if (!Addr) { + dbgs() << "PHITransAddr: null\n"; + return; + } + dbgs() << "PHITransAddr: " << *Addr << "\n"; + for (unsigned i = 0, e = InstInputs.size(); i != e; ++i) + dbgs() << " Input #" << i << " is " << *InstInputs[i] << "\n"; +} +#endif + + +static bool VerifySubExpr(Value *Expr, + SmallVectorImpl &InstInputs) { + // If this is a non-instruction value, there is nothing to do. + Instruction *I = dyn_cast(Expr); + if (!I) return true; + + // If it's an instruction, it is either in Tmp or its operands recursively + // are. + SmallVectorImpl::iterator Entry = + std::find(InstInputs.begin(), InstInputs.end(), I); + if (Entry != InstInputs.end()) { + InstInputs.erase(Entry); + return true; + } + + // If it isn't in the InstInputs list it is a subexpr incorporated into the + // address. Sanity check that it is phi translatable. + if (!CanPHITrans(I)) { + errs() << "Instruction in PHITransAddr is not phi-translatable:\n"; + errs() << *I << '\n'; + llvm_unreachable("Either something is missing from InstInputs or " + "CanPHITrans is wrong."); + } + + // Validate the operands of the instruction. + for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) + if (!VerifySubExpr(I->getOperand(i), InstInputs)) + return false; + + return true; +} + +/// Verify - Check internal consistency of this data structure. If the +/// structure is valid, it returns true. If invalid, it prints errors and +/// returns false. +bool PHITransAddr::Verify() const { + if (!Addr) return true; + + SmallVector Tmp(InstInputs.begin(), InstInputs.end()); + + if (!VerifySubExpr(Addr, Tmp)) + return false; + + if (!Tmp.empty()) { + errs() << "PHITransAddr contains extra instructions:\n"; + for (unsigned i = 0, e = InstInputs.size(); i != e; ++i) + errs() << " InstInput #" << i << " is " << *InstInputs[i] << "\n"; + llvm_unreachable("This is unexpected."); + } + + // a-ok. + return true; +} + + /// IsPotentiallyPHITranslatable - If this needs PHI translation, return true /// if we have some hope of doing it. This should be used as a filter to /// avoid calling PHITranslateValue in hopeless situations. @@ -23,176 +116,221 @@ bool PHITransAddr::IsPotentiallyPHITranslatable() 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(Addr); - if (isa(Inst) || - isa(Inst) || - isa(Inst) || - (Inst->getOpcode() == Instruction::And && - isa(Inst->getOperand(1)))) - return true; + return !Inst || CanPHITrans(Inst); +} - // cerr << "MEMDEP: Could not PHI translate: " << *Pointer; - // if (isa(PtrInst) || isa(PtrInst)) - // cerr << "OP:\t\t\t\t" << *PtrInst->getOperand(0); - return false; -} +static void RemoveInstInputs(Value *V, + SmallVectorImpl &InstInputs) { + Instruction *I = dyn_cast(V); + if (!I) return; + + // If the instruction is in the InstInputs list, remove it. + SmallVectorImpl::iterator Entry = + std::find(InstInputs.begin(), InstInputs.end(), I); + if (Entry != InstInputs.end()) { + InstInputs.erase(Entry); + return; + } + assert(!isa(I) && "Error, removing something that isn't an input"); + + // Otherwise, it must have instruction inputs itself. Zap them recursively. + for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) { + if (Instruction *Op = dyn_cast(I->getOperand(i))) + RemoveInstInputs(Op, InstInputs); + } +} Value *PHITransAddr::PHITranslateSubExpr(Value *V, BasicBlock *CurBB, - BasicBlock *PredBB) { + BasicBlock *PredBB, + const DominatorTree *DT) { // If this is a non-instruction value, it can't require PHI translation. Instruction *Inst = dyn_cast(V); - if (Inst == 0) return V; - + if (!Inst) return V; + // Determine whether 'Inst' is an input to our PHI translatable expression. bool isInput = std::count(InstInputs.begin(), InstInputs.end(), Inst); - - // If 'Inst' is not defined in this block, it is either an input, or an - // intermediate result. - if (Inst->getParent() != CurBB) { - // If it is an input, then it remains an input. - if (isInput) + + // Handle inputs instructions if needed. + if (isInput) { + if (Inst->getParent() != CurBB) { + // If it is an input defined in a different block, then it remains an + // input. return Inst; - - // Otherwise, it must be an intermediate result. See if its operands need - // to be phi translated, and if so, reconstruct it. - - if (BitCastInst *BC = dyn_cast(Inst)) { - Value *PHIIn = PHITranslateSubExpr(BC->getOperand(0), CurBB, PredBB); - if (PHIIn == 0) return 0; - if (PHIIn == BC->getOperand(0)) - return BC; - - // Find an available version of this cast. - - // Constants are trivial to find. - if (Constant *C = dyn_cast(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(*UI)) - if (BCI->getType() == BC->getType()) - return BCI; - } - return 0; } - - // Handle getelementptr with at least one PHI translatable operand. - if (GetElementPtrInst *GEP = dyn_cast(Inst)) { - SmallVector GEPOps; - BasicBlock *CurBB = GEP->getParent(); - bool AnyChanged = false; - for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) { - Value *GEPOp = PHITranslateSubExpr(GEP->getOperand(i), CurBB, PredBB); - if (GEPOp == 0) return 0; - - AnyChanged = GEPOp != GEP->getOperand(i); - GEPOps.push_back(GEPOp); - } - - if (!AnyChanged) - return GEP; - - // 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(*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; + + // If 'Inst' is defined in this block and is an input that needs to be phi + // translated, we need to incorporate the value into the expression or fail. + + // In either case, the instruction itself isn't an input any longer. + InstInputs.erase(std::find(InstInputs.begin(), InstInputs.end(), Inst)); + + // If this is a PHI, go ahead and translate it. + if (PHINode *PN = dyn_cast(Inst)) + return AddAsInput(PN->getIncomingValueForBlock(PredBB)); + + // If this is a non-phi value, and it is analyzable, we can incorporate it + // into the expression by making all instruction operands be inputs. + if (!CanPHITrans(Inst)) + return nullptr; + + // All instruction operands are now inputs (and of course, they may also be + // defined in this block, so they may need to be phi translated themselves. + for (unsigned i = 0, e = Inst->getNumOperands(); i != e; ++i) + if (Instruction *Op = dyn_cast(Inst->getOperand(i))) + InstInputs.push_back(Op); + } + + // Ok, it must be an intermediate result (either because it started that way + // or because we just incorporated it into the expression). See if its + // operands need to be phi translated, and if so, reconstruct it. + + if (CastInst *Cast = dyn_cast(Inst)) { + if (!isSafeToSpeculativelyExecute(Cast)) return nullptr; + Value *PHIIn = PHITranslateSubExpr(Cast->getOperand(0), CurBB, PredBB, DT); + if (!PHIIn) return nullptr; + if (PHIIn == Cast->getOperand(0)) + return Cast; + + // Find an available version of this cast. + + // Constants are trivial to find. + if (Constant *C = dyn_cast(PHIIn)) + return AddAsInput(ConstantExpr::getCast(Cast->getOpcode(), + C, Cast->getType())); + + // Otherwise we have to see if a casted version of the incoming pointer + // is available. If so, we can use it, otherwise we have to fail. + for (User *U : PHIIn->users()) { + if (CastInst *CastI = dyn_cast(U)) + if (CastI->getOpcode() == Cast->getOpcode() && + CastI->getType() == Cast->getType() && + (!DT || DT->dominates(CastI->getParent(), PredBB))) + return CastI; } - - // Handle add with a constant RHS. - if (Inst->getOpcode() == Instruction::Add && - isa(Inst->getOperand(1))) { - // PHI translate the LHS. - Constant *RHS = cast(Inst->getOperand(1)); - bool isNSW = cast(Inst)->hasNoSignedWrap(); - bool isNUW = cast(Inst)->hasNoUnsignedWrap(); - - Value *LHS = PHITranslateSubExpr(Inst->getOperand(0), CurBB, PredBB); - if (LHS == 0) return 0; - - // If the PHI translated LHS is an add of a constant, fold the immediates. - if (BinaryOperator *BOp = dyn_cast(LHS)) - if (BOp->getOpcode() == Instruction::Add) - if (ConstantInt *CI = dyn_cast(BOp->getOperand(1))) { - LHS = BOp->getOperand(0); - RHS = ConstantExpr::getAdd(RHS, CI); - isNSW = isNUW = false; + return nullptr; + } + + // Handle getelementptr with at least one PHI translatable operand. + if (GetElementPtrInst *GEP = dyn_cast(Inst)) { + SmallVector GEPOps; + bool AnyChanged = false; + for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) { + Value *GEPOp = PHITranslateSubExpr(GEP->getOperand(i), CurBB, PredBB, DT); + if (!GEPOp) return nullptr; + + AnyChanged |= GEPOp != GEP->getOperand(i); + GEPOps.push_back(GEPOp); + } + + if (!AnyChanged) + return GEP; + + // Simplify the GEP to handle 'gep x, 0' -> x etc. + if (Value *V = SimplifyGEPInst(GEPOps, DL, TLI, DT)) { + for (unsigned i = 0, e = GEPOps.size(); i != e; ++i) + RemoveInstInputs(GEPOps[i], InstInputs); + + return AddAsInput(V); + } + + // Scan to see if we have this GEP available. + Value *APHIOp = GEPOps[0]; + for (User *U : APHIOp->users()) { + if (GetElementPtrInst *GEPI = dyn_cast(U)) + if (GEPI->getType() == GEP->getType() && + GEPI->getNumOperands() == GEPOps.size() && + GEPI->getParent()->getParent() == CurBB->getParent() && + (!DT || DT->dominates(GEPI->getParent(), PredBB))) { + 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 nullptr; + } + + // Handle add with a constant RHS. + if (Inst->getOpcode() == Instruction::Add && + isa(Inst->getOperand(1))) { + // PHI translate the LHS. + Constant *RHS = cast(Inst->getOperand(1)); + bool isNSW = cast(Inst)->hasNoSignedWrap(); + bool isNUW = cast(Inst)->hasNoUnsignedWrap(); + + Value *LHS = PHITranslateSubExpr(Inst->getOperand(0), CurBB, PredBB, DT); + if (!LHS) return nullptr; + + // If the PHI translated LHS is an add of a constant, fold the immediates. + if (BinaryOperator *BOp = dyn_cast(LHS)) + if (BOp->getOpcode() == Instruction::Add) + if (ConstantInt *CI = dyn_cast(BOp->getOperand(1))) { + LHS = BOp->getOperand(0); + RHS = ConstantExpr::getAdd(RHS, CI); + isNSW = isNUW = false; + + // If the old 'LHS' was an input, add the new 'LHS' as an input. + if (std::count(InstInputs.begin(), InstInputs.end(), BOp)) { + RemoveInstInputs(BOp, InstInputs); + AddAsInput(LHS); } - - // 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(*UI)) - if (BO->getOperand(0) == LHS && BO->getOperand(1) == RHS && - BO->getParent()->getParent() == CurBB->getParent()) - return BO; - } - - return 0; + } + + // See if the add simplifies away. + if (Value *Res = SimplifyAddInst(LHS, RHS, isNSW, isNUW, DL, TLI, DT)) { + // If we simplified the operands, the LHS is no longer an input, but Res + // is. + RemoveInstInputs(LHS, InstInputs); + return AddAsInput(Res); + } + + // If we didn't modify the add, just return it. + if (LHS == Inst->getOperand(0) && RHS == Inst->getOperand(1)) + return Inst; + + // Otherwise, see if we have this add available somewhere. + for (User *U : LHS->users()) { + if (BinaryOperator *BO = dyn_cast(U)) + if (BO->getOpcode() == Instruction::Add && + BO->getOperand(0) == LHS && BO->getOperand(1) == RHS && + BO->getParent()->getParent() == CurBB->getParent() && + (!DT || DT->dominates(BO->getParent(), PredBB))) + return BO; } - - // Otherwise, we failed. - return 0; + + return nullptr; } - // Otherwise, it is defined in this block. It must be an input and must be - // phi translated. - assert(isInput && "Instruction defined in block must be an input"); - - - abort(); // unimplemented so far. + // Otherwise, we failed. + return nullptr; } /// PHITranslateValue - PHI translate the current address up the CFG from -/// CurBB to Pred, updating our state the reflect any needed changes. This -/// returns true on failure. -bool PHITransAddr::PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB) { - Addr = PHITranslateSubExpr(Addr, CurBB, PredBB); - return Addr == 0; -} +/// CurBB to Pred, updating our state to reflect any needed changes. If the +/// dominator tree DT is non-null, the translated value must dominate +/// PredBB. This returns true on failure and sets Addr to null. +bool PHITransAddr::PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB, + const DominatorTree *DT) { + assert(Verify() && "Invalid PHITransAddr!"); + Addr = PHITranslateSubExpr(Addr, CurBB, PredBB, DT); + assert(Verify() && "Invalid PHITransAddr!"); -/// GetAvailablePHITranslatedSubExpr - Return the value computed by -/// PHITranslateSubExpr if it dominates PredBB, otherwise return null. -Value *PHITransAddr:: -GetAvailablePHITranslatedSubExpr(Value *V, BasicBlock *CurBB,BasicBlock *PredBB, - const DominatorTree &DT) { - // See if PHI translation succeeds. - V = PHITranslateSubExpr(V, CurBB, PredBB); - - // Make sure the value is live in the predecessor. - if (Instruction *Inst = dyn_cast_or_null(V)) - if (!DT.dominates(Inst->getParent(), PredBB)) - return 0; - return V; -} + if (DT) { + // Make sure the value is live in the predecessor. + if (Instruction *Inst = dyn_cast_or_null(Addr)) + if (!DT->dominates(Inst->getParent(), PredBB)) + Addr = nullptr; + } + return Addr == nullptr; +} /// PHITranslateWithInsertion - PHI translate this value into the specified /// predecessor block, inserting a computation of the value if it is @@ -206,17 +344,17 @@ PHITranslateWithInsertion(BasicBlock *CurBB, BasicBlock *PredBB, const DominatorTree &DT, SmallVectorImpl &NewInsts) { unsigned NISize = NewInsts.size(); - + // Attempt to PHI translate with insertion. Addr = InsertPHITranslatedSubExpr(Addr, CurBB, PredBB, DT, NewInsts); - + // If successful, return the new value. if (Addr) return Addr; - + // If not, destroy any intermediate instructions inserted. while (NewInsts.size() != NISize) NewInsts.pop_back_val()->eraseFromParent(); - return 0; + return nullptr; } @@ -231,27 +369,30 @@ InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB, SmallVectorImpl &NewInsts) { // See if we have a version of this value already available and dominating // PredBB. If so, there is no need to insert a new instance of it. - if (Value *Res = GetAvailablePHITranslatedSubExpr(InVal, CurBB, PredBB, DT)) - return Res; + PHITransAddr Tmp(InVal, DL); + if (!Tmp.PHITranslateValue(CurBB, PredBB, &DT)) + return Tmp.getAddr(); // If we don't have an available version of this value, it must be an // instruction. Instruction *Inst = cast(InVal); - - // Handle bitcast of PHI translatable value. - if (BitCastInst *BC = dyn_cast(Inst)) { - Value *OpVal = InsertPHITranslatedSubExpr(BC->getOperand(0), + + // Handle cast of PHI translatable value. + if (CastInst *Cast = dyn_cast(Inst)) { + if (!isSafeToSpeculativelyExecute(Cast)) return nullptr; + Value *OpVal = InsertPHITranslatedSubExpr(Cast->getOperand(0), CurBB, PredBB, 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()); + if (!OpVal) return nullptr; + + // Otherwise insert a cast at the end of PredBB. + CastInst *New = CastInst::Create(Cast->getOpcode(), + 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(Inst)) { SmallVector GEPOps; @@ -259,24 +400,24 @@ InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB, for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) { Value *OpVal = InsertPHITranslatedSubExpr(GEP->getOperand(i), CurBB, PredBB, DT, NewInsts); - if (OpVal == 0) return 0; + if (!OpVal) return nullptr; GEPOps.push_back(OpVal); } - - GetElementPtrInst *Result = - GetElementPtrInst::Create(GEPOps[0], GEPOps.begin()+1, GEPOps.end(), - InVal->getName()+".phi.trans.insert", - PredBB->getTerminator()); + + GetElementPtrInst *Result = + GetElementPtrInst::Create(GEPOps[0], makeArrayRef(GEPOps).slice(1), + 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(Inst->getOperand(1))) { @@ -284,7 +425,7 @@ InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB, Value *OpVal = InsertPHITranslatedSubExpr(Inst->getOperand(0), CurBB, PredBB, DT, NewInsts); if (OpVal == 0) return 0; - + BinaryOperator *Res = BinaryOperator::CreateAdd(OpVal, Inst->getOperand(1), InVal->getName()+".phi.trans.insert", PredBB->getTerminator()); @@ -294,6 +435,6 @@ InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB, return Res; } #endif - - return 0; + + return nullptr; }