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Diffstat (limited to 'gnu/llvm/lib/Analysis/PHITransAddr.cpp')
| -rw-r--r-- | gnu/llvm/lib/Analysis/PHITransAddr.cpp | 440 |
1 files changed, 0 insertions, 440 deletions
diff --git a/gnu/llvm/lib/Analysis/PHITransAddr.cpp b/gnu/llvm/lib/Analysis/PHITransAddr.cpp deleted file mode 100644 index 858f08f6537..00000000000 --- a/gnu/llvm/lib/Analysis/PHITransAddr.cpp +++ /dev/null @@ -1,440 +0,0 @@ -//===- PHITransAddr.cpp - PHI Translation for Addresses -------------------===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This file implements the PHITransAddr class. -// -//===----------------------------------------------------------------------===// - -#include "llvm/Analysis/PHITransAddr.h" -#include "llvm/Analysis/InstructionSimplify.h" -#include "llvm/Analysis/ValueTracking.h" -#include "llvm/Config/llvm-config.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<PHINode>(Inst) || - isa<GetElementPtrInst>(Inst)) - return true; - - if (isa<CastInst>(Inst) && - isSafeToSpeculativelyExecute(Inst)) - return true; - - if (Inst->getOpcode() == Instruction::Add && - isa<ConstantInt>(Inst->getOperand(1))) - return true; - - // 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; -} - -#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) -LLVM_DUMP_METHOD 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<Instruction*> &InstInputs) { - // If this is a non-instruction value, there is nothing to do. - Instruction *I = dyn_cast<Instruction>(Expr); - if (!I) return true; - - // If it's an instruction, it is either in Tmp or its operands recursively - // are. - SmallVectorImpl<Instruction *>::iterator Entry = find(InstInputs, 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<Instruction*, 8> 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. -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<Instruction>(Addr); - return !Inst || CanPHITrans(Inst); -} - - -static void RemoveInstInputs(Value *V, - SmallVectorImpl<Instruction*> &InstInputs) { - Instruction *I = dyn_cast<Instruction>(V); - if (!I) return; - - // If the instruction is in the InstInputs list, remove it. - SmallVectorImpl<Instruction *>::iterator Entry = find(InstInputs, I); - if (Entry != InstInputs.end()) { - InstInputs.erase(Entry); - return; - } - - assert(!isa<PHINode>(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<Instruction>(I->getOperand(i))) - RemoveInstInputs(Op, InstInputs); - } -} - -Value *PHITransAddr::PHITranslateSubExpr(Value *V, BasicBlock *CurBB, - BasicBlock *PredBB, - const DominatorTree *DT) { - // If this is a non-instruction value, it can't require PHI translation. - Instruction *Inst = dyn_cast<Instruction>(V); - if (!Inst) return V; - - // Determine whether 'Inst' is an input to our PHI translatable expression. - bool isInput = is_contained(InstInputs, 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(find(InstInputs, Inst)); - - // If this is a PHI, go ahead and translate it. - if (PHINode *PN = dyn_cast<PHINode>(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<Instruction>(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<CastInst>(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<Constant>(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<CastInst>(U)) - if (CastI->getOpcode() == Cast->getOpcode() && - CastI->getType() == Cast->getType() && - (!DT || DT->dominates(CastI->getParent(), PredBB))) - return CastI; - } - return nullptr; - } - - // Handle getelementptr with at least one PHI translatable operand. - if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) { - SmallVector<Value*, 8> 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(GEP->getSourceElementType(), - GEPOps, {DL, TLI, DT, AC})) { - 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<GetElementPtrInst>(U)) - if (GEPI->getType() == GEP->getType() && - GEPI->getNumOperands() == GEPOps.size() && - GEPI->getParent()->getParent() == CurBB->getParent() && - (!DT || DT->dominates(GEPI->getParent(), PredBB))) { - if (std::equal(GEPOps.begin(), GEPOps.end(), GEPI->op_begin())) - return GEPI; - } - } - return nullptr; - } - - // Handle add with a constant RHS. - if (Inst->getOpcode() == Instruction::Add && - isa<ConstantInt>(Inst->getOperand(1))) { - // PHI translate the LHS. - Constant *RHS = cast<ConstantInt>(Inst->getOperand(1)); - bool isNSW = cast<BinaryOperator>(Inst)->hasNoSignedWrap(); - bool isNUW = cast<BinaryOperator>(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<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; - - // If the old 'LHS' was an input, add the new 'LHS' as an input. - if (is_contained(InstInputs, BOp)) { - RemoveInstInputs(BOp, InstInputs); - AddAsInput(LHS); - } - } - - // See if the add simplifies away. - if (Value *Res = SimplifyAddInst(LHS, RHS, isNSW, isNUW, {DL, TLI, DT, AC})) { - // 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<BinaryOperator>(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 nullptr; - } - - // Otherwise, we failed. - return nullptr; -} - - -/// PHITranslateValue - PHI translate the current address up the CFG from -/// CurBB to Pred, updating our state to reflect any needed changes. If -/// 'MustDominate' is true, 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, - bool MustDominate) { - assert(DT || !MustDominate); - assert(Verify() && "Invalid PHITransAddr!"); - if (DT && DT->isReachableFromEntry(PredBB)) - Addr = - PHITranslateSubExpr(Addr, CurBB, PredBB, MustDominate ? DT : nullptr); - else - Addr = nullptr; - assert(Verify() && "Invalid PHITransAddr!"); - - if (MustDominate) - // Make sure the value is live in the predecessor. - if (Instruction *Inst = dyn_cast_or_null<Instruction>(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 -/// unavailable. -/// -/// All newly created instructions are added to the NewInsts list. This -/// returns null on failure. -/// -Value *PHITransAddr:: -PHITranslateWithInsertion(BasicBlock *CurBB, BasicBlock *PredBB, - const DominatorTree &DT, - SmallVectorImpl<Instruction*> &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 nullptr; -} - - -/// 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. -/// This returns null on failure. -/// -Value *PHITransAddr:: -InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB, - BasicBlock *PredBB, const DominatorTree &DT, - SmallVectorImpl<Instruction*> &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. - PHITransAddr Tmp(InVal, DL, AC); - if (!Tmp.PHITranslateValue(CurBB, PredBB, &DT, /*MustDominate=*/true)) - return Tmp.getAddr(); - - // We don't need to PHI translate values which aren't instructions. - auto *Inst = dyn_cast<Instruction>(InVal); - if (!Inst) - return nullptr; - - // Handle cast of PHI translatable value. - if (CastInst *Cast = dyn_cast<CastInst>(Inst)) { - if (!isSafeToSpeculativelyExecute(Cast)) return nullptr; - Value *OpVal = InsertPHITranslatedSubExpr(Cast->getOperand(0), - CurBB, PredBB, DT, NewInsts); - 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()); - New->setDebugLoc(Inst->getDebugLoc()); - 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 = InsertPHITranslatedSubExpr(GEP->getOperand(i), - CurBB, PredBB, DT, NewInsts); - if (!OpVal) return nullptr; - GEPOps.push_back(OpVal); - } - - GetElementPtrInst *Result = GetElementPtrInst::Create( - GEP->getSourceElementType(), GEPOps[0], makeArrayRef(GEPOps).slice(1), - InVal->getName() + ".phi.trans.insert", PredBB->getTerminator()); - Result->setDebugLoc(Inst->getDebugLoc()); - 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 = 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()); - Res->setHasNoSignedWrap(cast<BinaryOperator>(Inst)->hasNoSignedWrap()); - Res->setHasNoUnsignedWrap(cast<BinaryOperator>(Inst)->hasNoUnsignedWrap()); - NewInsts.push_back(Res); - return Res; - } -#endif - - return nullptr; -} |