//===----------------------------------------------------------------------===//
#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<PHINode>(Inst) ||
- isa<BitCastInst>(Inst) ||
isa<GetElementPtrInst>(Inst))
return true;
-
- if (Inst->getOpcode() == Instruction::And &&
+
+ 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)
+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 =
+ 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<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.
// 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 == 0 || CanPHITrans(Inst);
+ 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 =
+ std::find(InstInputs.begin(), InstInputs.end(), 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) {
+ 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 == 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?");
-
+ if (!Inst) return V;
+
+ // Determine whether 'Inst' is an input to our PHI translatable expression.
+ bool isInput =
+ std::find(InstInputs.begin(), InstInputs.end(), Inst) != InstInputs.end();
+
+ // 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<PHINode>(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));
-
+ 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);
-
- } 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<BitCastInst>(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<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 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<BitCastInst>(*UI))
- if (BCI->getType() == BC->getType())
- return BCI;
+ 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 0;
+ return nullptr;
}
-
+
// Handle getelementptr with at least one PHI translatable operand.
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
SmallVector<Value*, 8> 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);
+ 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 V;
-
+ if (Value *V = SimplifyGEPInst(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 (Value::use_iterator UI = APHIOp->use_begin(), E = APHIOp->use_end();
- UI != E; ++UI) {
- if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(*UI))
+ 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()) {
- bool Mismatch = false;
- for (unsigned i = 0, e = GEPOps.size(); i != e; ++i)
- if (GEPI->getOperand(i) != GEPOps[i]) {
- Mismatch = true;
- break;
- }
- if (!Mismatch)
+ GEPI->getParent()->getParent() == CurBB->getParent() &&
+ (!DT || DT->dominates(GEPI->getParent(), PredBB))) {
+ if (std::equal(GEPOps.begin(), GEPOps.end(), GEPI->op_begin()))
return GEPI;
}
}
- return 0;
+ return nullptr;
}
-
+
// Handle add with a constant RHS.
if (Inst->getOpcode() == Instruction::Add &&
isa<ConstantInt>(Inst->getOperand(1))) {
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);
- 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<BinaryOperator>(LHS))
if (BOp->getOpcode() == Instruction::Add)
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::find(InstInputs.begin(), InstInputs.end(), BOp) !=
+ InstInputs.end()) {
+ RemoveInstInputs(BOp, InstInputs);
+ AddAsInput(LHS);
+ }
}
-
+
// See if the add simplifies away.
- if (Value *Res = SimplifyAddInst(LHS, RHS, isNSW, isNUW, TD))
- return Res;
-
+ 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 (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())
+ 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 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.
-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
+/// '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!");
-/// 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<Instruction>(V))
- if (!DT.dominates(Inst->getParent(), PredBB))
- return 0;
- return V;
-}
+ 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
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 0;
+ return nullptr;
}
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.
- if (Value *Res = GetAvailablePHITranslatedSubExpr(InVal, CurBB, PredBB, DT))
- return Res;
+ PHITransAddr Tmp(InVal, DL, AC);
+ if (!Tmp.PHITranslateValue(CurBB, PredBB, &DT, /*MustDominate=*/true))
+ return Tmp.getAddr();
// 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 = InsertPHITranslatedSubExpr(BC->getOperand(0),
+
+ // 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 == 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());
+ 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;
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(
+ 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))) {
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());
return Res;
}
#endif
-
- return 0;
+
+ return nullptr;
}
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