#include "llvm/Analysis/PHITransAddr.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
using namespace llvm;
static bool CanPHITrans(Instruction *Inst) {
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<Instruction*> &InstInputs) {
+ // If this is a non-instruction value, there is nothing to do.
+ Instruction *I = dyn_cast<Instruction>(Expr);
+ if (I == 0) 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() << "Non phi translatable instruction found in PHITransAddr, either "
+ "something is missing from InstInputs or CanPHITrans is wrong:\n";
+ errs() << *I << '\n';
+ return false;
+ }
+
+ // 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<Instruction*, 8> Tmp(InstInputs.begin(), InstInputs.end());
+
+ if (!VerifySubExpr(Addr, Tmp))
+ return false;
+
+ if (!Tmp.empty()) {
+ errs() << "PHITransAddr inconsistent, contains extra instructions:\n";
+ for (unsigned i = 0, e = InstInputs.size(); i != e; ++i)
+ errs() << " InstInput #" << i << " is " << *InstInputs[i] << "\n";
+ return false;
+ }
+
+ // 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.
}
-static void RemoveInstInputs(Instruction *I,
+static void RemoveInstInputs(Value *V,
SmallVectorImpl<Instruction*> &InstInputs) {
+ Instruction *I = dyn_cast<Instruction>(V);
+ if (I == 0) return;
+
// If the instruction is in the InstInputs list, remove it.
SmallVectorImpl<Instruction*>::iterator Entry =
std::find(InstInputs.begin(), InstInputs.end(), I);
return;
}
+ assert(!isa<PHINode>(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<Instruction>(I->getOperand(i))) {
+ if (Instruction *Op = dyn_cast<Instruction>(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<Instruction>(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<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?");
+ // 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<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));
-
+
// 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
// 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);
+ Value *PHIIn = PHITranslateSubExpr(BC->getOperand(0), CurBB, PredBB, DT);
if (PHIIn == 0) return 0;
if (PHIIn == BC->getOperand(0))
return BC;
// Constants are trivial to find.
if (Constant *C = dyn_cast<Constant>(PHIIn))
- return ReplaceInstWithValue(BC, ConstantExpr::getBitCast(C,
- BC->getType()));
+ return AddAsInput(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<BitCastInst>(*UI))
- if (BCI->getType() == BC->getType())
+ if (BCI->getType() == BC->getType() &&
+ (!DT || DT->dominates(BCI->getParent(), PredBB)))
return BCI;
}
return 0;
// 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);
+ Value *GEPOp = PHITranslateSubExpr(GEP->getOperand(i), CurBB, PredBB, DT);
if (GEPOp == 0) return 0;
AnyChanged |= GEPOp != GEP->getOperand(i);
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[0], GEPOps.size(), TD)) {
+ 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];
if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(*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]) {
bool isNSW = cast<BinaryOperator>(Inst)->hasNoSignedWrap();
bool isNUW = cast<BinaryOperator>(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.
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)) {
+ // 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())
+ 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;
}
/// 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<Instruction>(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<Instruction>(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
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, 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.
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