X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FPHITransAddr.cpp;h=38cb1c91f8f830701951d5d628cfb26d7697554f;hb=d6fc26217e194372cabe4ef9e2514beac511a943;hp=edb41f7f4cc35f283c00c37136cf6435852b9861;hpb=43678f41a37c077f28517c2e4889cca88cada6ce;p=oota-llvm.git diff --git a/lib/Analysis/PHITransAddr.cpp b/lib/Analysis/PHITransAddr.cpp index edb41f7f4cc..38cb1c91f8f 100644 --- a/lib/Analysis/PHITransAddr.cpp +++ b/lib/Analysis/PHITransAddr.cpp @@ -12,26 +12,101 @@ //===----------------------------------------------------------------------===// #include "llvm/Analysis/PHITransAddr.h" +#include "llvm/Analysis/ValueTracking.h" +#include "llvm/Constants.h" +#include "llvm/Instructions.h" #include "llvm/Analysis/Dominators.h" #include "llvm/Analysis/InstructionSimplify.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) || 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; } +void PHITransAddr::dump() const { + if (Addr == 0) { + 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"; +} + + +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 == 0) 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() << "Non phi translatable instruction found in PHITransAddr:\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 == 0) 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. @@ -43,8 +118,11 @@ bool PHITransAddr::IsPotentiallyPHITranslatable() const { } -static void RemoveInstInputs(Instruction *I, +static void RemoveInstInputs(Value *V, SmallVectorImpl &InstInputs) { + Instruction *I = dyn_cast(V); + if (I == 0) return; + // If the instruction is in the InstInputs list, remove it. SmallVectorImpl::iterator Entry = std::find(InstInputs.begin(), InstInputs.end(), I); @@ -52,124 +130,110 @@ static void RemoveInstInputs(Instruction *I, 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. - bool HadInstInputs = false; for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) { - if (Instruction *Op = dyn_cast(I->getOperand(i))) { + if (Instruction *Op = dyn_cast(I->getOperand(i))) RemoveInstInputs(Op, InstInputs); - HadInstInputs = true; - } } - - // This instruction had to have operands in the instinputs list or it should - // have been in the list itself. If not, the list is broken. - assert(HadInstInputs && "InstInputs list inconsistent!"); } -/// ReplaceInstWithValue - Remove any instruction inputs in the InstInputs -/// array that are due to the specified instruction that is about to be -/// removed from the address, and add any corresponding to V. This returns V. -Value *PHITransAddr::ReplaceInstWithValue(Instruction *I, Value *V) { - // Remove the old instruction from InstInputs. - RemoveInstInputs(I, InstInputs); - - // If V is an instruction, it is now an input. - if (Instruction *VI = dyn_cast(V)) - InstInputs.push_back(VI); - return V; -} - - 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' is defined in this block, it must be an input that needs to be - // phi translated or an intermediate expression that needs to be incorporated - // into the expression. - if (Inst->getParent() == CurBB) { - assert(std::count(InstInputs.begin(), InstInputs.end(), Inst) && - "Not an input?"); - + + // Determine whether 'Inst' is an input to our PHI translatable expression. + bool isInput = std::count(InstInputs.begin(), InstInputs.end(), Inst); + + // 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; + } + + // 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 PN->getIncomingValueForBlock(PredBB); + 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 0; - - // Okay, we can incorporate it, this instruction is no longer an input. - InstInputs.erase(std::find(InstInputs.begin(), InstInputs.end(), Inst)); - + // 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); - - } else { - // Determine whether 'Inst' is an input to our PHI translatable expression. - bool isInput = std::count(InstInputs.begin(), InstInputs.end(), Inst); - - // If it is an input defined in a different block, then it remains an input. - if (isInput) - return Inst; } // 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 (BitCastInst *BC = dyn_cast(Inst)) { - Value *PHIIn = PHITranslateSubExpr(BC->getOperand(0), CurBB, PredBB); + + if (CastInst *Cast = dyn_cast(Inst)) { + if (!isSafeToSpeculativelyExecute(Cast)) return 0; + Value *PHIIn = PHITranslateSubExpr(Cast->getOperand(0), CurBB, PredBB, DT); if (PHIIn == 0) return 0; - if (PHIIn == BC->getOperand(0)) - return BC; - + 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 ReplaceInstWithValue(BC, ConstantExpr::getBitCast(C, - BC->getType())); - - // Otherwise we have to see if a bitcasted version of the incoming pointer + 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 (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; + if (CastInst *CastI = dyn_cast(*UI)) + if (CastI->getOpcode() == Cast->getOpcode() && + CastI->getType() == Cast->getType() && + (!DT || DT->dominates(CastI->getParent(), PredBB))) + return CastI; } 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); + Value *GEPOp = PHITranslateSubExpr(GEP->getOperand(i), CurBB, PredBB, DT); 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 ReplaceInstWithValue(GEP, V); - + if (Value *V = SimplifyGEPInst(GEPOps, TD, 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 (Value::use_iterator UI = APHIOp->use_begin(), E = APHIOp->use_end(); @@ -177,7 +241,8 @@ Value *PHITransAddr::PHITranslateSubExpr(Value *V, BasicBlock *CurBB, if (GetElementPtrInst *GEPI = dyn_cast(*UI)) if (GEPI->getType() == GEP->getType() && GEPI->getNumOperands() == GEPOps.size() && - GEPI->getParent()->getParent() == CurBB->getParent()) { + 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]) { @@ -190,7 +255,7 @@ Value *PHITransAddr::PHITranslateSubExpr(Value *V, BasicBlock *CurBB, } return 0; } - + // Handle add with a constant RHS. if (Inst->getOpcode() == Instruction::Add && isa(Inst->getOperand(1))) { @@ -198,10 +263,10 @@ Value *PHITransAddr::PHITranslateSubExpr(Value *V, BasicBlock *CurBB, Constant *RHS = cast(Inst->getOperand(1)); bool isNSW = cast(Inst)->hasNoSignedWrap(); bool isNUW = cast(Inst)->hasNoUnsignedWrap(); - - Value *LHS = PHITranslateSubExpr(Inst->getOperand(0), CurBB, PredBB); + + Value *LHS = PHITranslateSubExpr(Inst->getOperand(0), CurBB, PredBB, DT); 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) @@ -209,55 +274,64 @@ Value *PHITransAddr::PHITranslateSubExpr(Value *V, BasicBlock *CurBB, 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 ReplaceInstWithValue(Inst, Res); - + if (Value *Res = SimplifyAddInst(LHS, RHS, isNSW, isNUW, TD, 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 (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()) + 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; } - + return 0; } - + // Otherwise, we failed. return 0; } /// 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 and sets Addr to null. -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) const { - PHITransAddr Tmp(V, TD); - Tmp.PHITranslateValue(CurBB, PredBB); - - // See if PHI translation succeeds. - V = Tmp.getAddr(); - - // 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 = 0; + } + return Addr == 0; +} /// PHITranslateWithInsertion - PHI translate this value into the specified /// predecessor block, inserting a computation of the value if it is @@ -271,13 +345,13 @@ 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(); @@ -296,27 +370,30 @@ 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, TD); + 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 0; + 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()); + + // 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; @@ -327,21 +404,21 @@ InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB, 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()); + + 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))) { @@ -349,7 +426,7 @@ 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()); @@ -359,6 +436,6 @@ InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB, return Res; } #endif - + return 0; }