X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FPHITransAddr.cpp;h=bfe86425119be24c0a87d9414c16e8ebe019dabe;hb=66b380b6b60f96816346fa50f049b5463512387f;hp=04f3f5dcfc9c683e38363bd25892af8ec2229564;hpb=e09e98c2de28a7dbbc4d3712c174596443a7a3f1;p=oota-llvm.git diff --git a/lib/Analysis/PHITransAddr.cpp b/lib/Analysis/PHITransAddr.cpp index 04f3f5dcfc9..bfe86425119 100644 --- a/lib/Analysis/PHITransAddr.cpp +++ b/lib/Analysis/PHITransAddr.cpp @@ -12,44 +12,54 @@ //===----------------------------------------------------------------------===// #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) || 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 == 0) { - errs() << "PHITransAddr: null\n"; + if (!Addr) { + dbgs() << "PHITransAddr: null\n"; return; } - errs() << "PHITransAddr: " << *Addr << "\n"; + dbgs() << "PHITransAddr: " << *Addr << "\n"; for (unsigned i = 0, e = InstInputs.size(); i != e; ++i) - errs() << " Input #" << i << " is " << *InstInputs[i] << "\n"; + 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 == 0) return true; - + if (!I) return true; + // If it's an instruction, it is either in Tmp or its operands recursively // are. SmallVectorImpl::iterator Entry = @@ -58,16 +68,16 @@ static bool VerifySubExpr(Value *Expr, 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, either " - "something is missing from InstInputs or CanPHITrans is wrong:\n"; + errs() << "Instruction in PHITransAddr is not phi-translatable:\n"; errs() << *I << '\n'; - return false; + 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)) @@ -80,20 +90,20 @@ static bool VerifySubExpr(Value *Expr, /// 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 (!Addr) return true; + + SmallVector Tmp(InstInputs.begin(), InstInputs.end()); + if (!VerifySubExpr(Addr, Tmp)) return false; - + if (!Tmp.empty()) { - errs() << "PHITransAddr inconsistent, contains extra instructions:\n"; + errs() << "PHITransAddr contains extra instructions:\n"; for (unsigned i = 0, e = InstInputs.size(); i != e; ++i) errs() << " InstInput #" << i << " is " << *InstInputs[i] << "\n"; - return false; + llvm_unreachable("This is unexpected."); } - + // a-ok. return true; } @@ -106,12 +116,15 @@ 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); - return Inst == 0 || CanPHITrans(Inst); + return !Inst || CanPHITrans(Inst); } -static void RemoveInstInputs(Instruction *I, +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); @@ -119,41 +132,23 @@ 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) return V; + // Determine whether 'Inst' is an input to our PHI translatable expression. bool isInput = std::count(InstInputs.begin(), InstInputs.end(), Inst); @@ -168,18 +163,18 @@ Value *PHITransAddr::PHITranslateSubExpr(Value *V, BasicBlock *CurBB, // 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 ReplaceInstWithValue(PN, 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; - - // The instruction itself isn't an input any longer. - InstInputs.erase(std::find(InstInputs.begin(), InstInputs.end(), 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) @@ -190,59 +185,64 @@ Value *PHITransAddr::PHITranslateSubExpr(Value *V, BasicBlock *CurBB, // 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 (PHIIn == 0) return 0; - if (PHIIn == BC->getOperand(0)) - return BC; - + + 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 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; + 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; } - return 0; + return nullptr; } - + // 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; - + 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[0], GEPOps.size(), TD)) - return ReplaceInstWithValue(GEP, V); - + 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 (Value::use_iterator UI = APHIOp->use_begin(), E = APHIOp->use_end(); - UI != E; ++UI) { - if (GetElementPtrInst *GEPI = dyn_cast(*UI)) + 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()) { + 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]) { @@ -253,9 +253,9 @@ Value *PHITransAddr::PHITranslateSubExpr(Value *V, BasicBlock *CurBB, return GEPI; } } - return 0; + return nullptr; } - + // Handle add with a constant RHS. if (Inst->getOpcode() == Instruction::Add && isa(Inst->getOperand(1))) { @@ -263,10 +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); - if (LHS == 0) return 0; - + + 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) @@ -274,57 +274,63 @@ 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, 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 (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()) + 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; } - - return 0; + + return nullptr; } - + // Otherwise, we failed. - return 0; + 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 and sets Addr to null. -bool PHITransAddr::PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB) { +/// 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); + Addr = PHITranslateSubExpr(Addr, CurBB, PredBB, DT); assert(Verify() && "Invalid PHITransAddr!"); - return Addr == 0; -} -/// 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 = nullptr; + } + return Addr == nullptr; +} /// PHITranslateWithInsertion - PHI translate this value into the specified /// predecessor block, inserting a computation of the value if it is @@ -338,17 +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; } @@ -363,27 +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; @@ -391,24 +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))) { @@ -416,7 +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()); @@ -426,6 +435,6 @@ InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB, return Res; } #endif - - return 0; + + return nullptr; }