#include "llvm/Analysis/ScalarEvolutionExpander.h"
#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/IntrinsicInst.h"
#include "llvm/LLVMContext.h"
#include "llvm/Target/TargetData.h"
#include "llvm/ADT/STLExtras.h"
Instruction *I = CastInst::Create(Op, V, Ty, V->getName(),
A->getParent()->getEntryBlock().begin());
- InsertedValues.insert(I);
+ rememberInstruction(I);
return I;
}
It = cast<InvokeInst>(I)->getNormalDest()->begin();
while (isa<PHINode>(It)) ++It;
if (It != BasicBlock::iterator(CI)) {
- // Recreate the cast at the beginning of the entry block.
+ // Recreate the cast after the user.
// The old cast is left in place in case it is being used
// as an insert point.
Instruction *NewCI = CastInst::Create(Op, V, Ty, "", It);
NewCI->takeName(CI);
CI->replaceAllUsesWith(NewCI);
+ rememberInstruction(NewCI);
return NewCI;
}
+ rememberInstruction(CI);
return CI;
}
}
IP = II->getNormalDest()->begin();
while (isa<PHINode>(IP)) ++IP;
Instruction *CI = CastInst::Create(Op, V, Ty, V->getName(), IP);
- InsertedValues.insert(CI);
+ rememberInstruction(CI);
return CI;
}
if (IP != BlockBegin) {
--IP;
for (; ScanLimit; --IP, --ScanLimit) {
+ // Don't count dbg.value against the ScanLimit, to avoid perturbing the
+ // generated code.
+ if (isa<DbgInfoIntrinsic>(IP))
+ ScanLimit++;
if (IP->getOpcode() == (unsigned)Opcode && IP->getOperand(0) == LHS &&
IP->getOperand(1) == RHS)
return IP;
}
}
+ // Save the original insertion point so we can restore it when we're done.
+ BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
+ BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+
+ // Move the insertion point out of as many loops as we can.
+ while (const Loop *L = SE.LI->getLoopFor(Builder.GetInsertBlock())) {
+ if (!L->isLoopInvariant(LHS) || !L->isLoopInvariant(RHS)) break;
+ BasicBlock *Preheader = L->getLoopPreheader();
+ if (!Preheader) break;
+
+ // Ok, move up a level.
+ Builder.SetInsertPoint(Preheader, Preheader->getTerminator());
+ }
+
// If we haven't found this binop, insert it.
Value *BO = Builder.CreateBinOp(Opcode, LHS, RHS, "tmp");
- InsertedValues.insert(BO);
+ rememberInstruction(BO);
+
+ // Restore the original insert point.
+ if (SaveInsertBB)
+ restoreInsertPoint(SaveInsertBB, SaveInsertPt);
+
return BO;
}
/// FactorOutConstant - Test if S is divisible by Factor, using signed
/// division. If so, update S with Factor divided out and return true.
-/// S need not be evenly divisble if a reasonable remainder can be
+/// S need not be evenly divisible if a reasonable remainder can be
/// computed.
/// TODO: When ScalarEvolution gets a SCEVSDivExpr, this can be made
/// unnecessary; in its place, just signed-divide Ops[i] by the scale and
const SCEVConstant *FC = cast<SCEVConstant>(Factor);
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(M->getOperand(0)))
if (!C->getValue()->getValue().srem(FC->getValue()->getValue())) {
- const SmallVectorImpl<const SCEV *> &MOperands = M->getOperands();
- SmallVector<const SCEV *, 4> NewMulOps(MOperands.begin(),
- MOperands.end());
+ SmallVector<const SCEV *, 4> NewMulOps(M->op_begin(), M->op_end());
NewMulOps[0] =
SE.getConstant(C->getValue()->getValue().sdiv(
FC->getValue()->getValue()));
const SCEV *Remainder = SE.getIntegerSCEV(0, SOp->getType());
if (FactorOutConstant(SOp, Remainder, Factor, SE, TD) &&
Remainder->isZero()) {
- const SmallVectorImpl<const SCEV *> &MOperands = M->getOperands();
- SmallVector<const SCEV *, 4> NewMulOps(MOperands.begin(),
- MOperands.end());
+ SmallVector<const SCEV *, 4> NewMulOps(M->op_begin(), M->op_end());
NewMulOps[i] = SOp;
S = SE.getMulExpr(NewMulOps);
return true;
SE.getAddExpr(NoAddRecs);
// If it returned an add, use the operands. Otherwise it simplified
// the sum into a single value, so just use that.
+ Ops.clear();
if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(Sum))
- Ops = Add->getOperands();
- else {
- Ops.clear();
- if (!Sum->isZero())
- Ops.push_back(Sum);
- }
+ Ops.insert(Ops.end(), Add->op_begin(), Add->op_end());
+ else if (!Sum->isZero())
+ Ops.push_back(Sum);
// Then append the addrecs.
Ops.insert(Ops.end(), AddRecs.begin(), AddRecs.end());
}
// the indices index into the element or field type selected by the
// preceding index.
for (;;) {
- const SCEV *ElSize = SE.getAllocSizeExpr(ElTy);
// If the scale size is not 0, attempt to factor out a scale for
// array indexing.
SmallVector<const SCEV *, 8> ScaledOps;
- if (ElTy->isSized() && !ElSize->isZero()) {
- SmallVector<const SCEV *, 8> NewOps;
- for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
- const SCEV *Op = Ops[i];
- const SCEV *Remainder = SE.getIntegerSCEV(0, Ty);
- if (FactorOutConstant(Op, Remainder, ElSize, SE, SE.TD)) {
- // Op now has ElSize factored out.
- ScaledOps.push_back(Op);
- if (!Remainder->isZero())
- NewOps.push_back(Remainder);
- AnyNonZeroIndices = true;
- } else {
- // The operand was not divisible, so add it to the list of operands
- // we'll scan next iteration.
- NewOps.push_back(Ops[i]);
+ if (ElTy->isSized()) {
+ const SCEV *ElSize = SE.getSizeOfExpr(ElTy);
+ if (!ElSize->isZero()) {
+ SmallVector<const SCEV *, 8> NewOps;
+ for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
+ const SCEV *Op = Ops[i];
+ const SCEV *Remainder = SE.getIntegerSCEV(0, Ty);
+ if (FactorOutConstant(Op, Remainder, ElSize, SE, SE.TD)) {
+ // Op now has ElSize factored out.
+ ScaledOps.push_back(Op);
+ if (!Remainder->isZero())
+ NewOps.push_back(Remainder);
+ AnyNonZeroIndices = true;
+ } else {
+ // The operand was not divisible, so add it to the list of operands
+ // we'll scan next iteration.
+ NewOps.push_back(Ops[i]);
+ }
+ }
+ // If we made any changes, update Ops.
+ if (!ScaledOps.empty()) {
+ Ops = NewOps;
+ SimplifyAddOperands(Ops, Ty, SE);
}
- }
- // If we made any changes, update Ops.
- if (!ScaledOps.empty()) {
- Ops = NewOps;
- SimplifyAddOperands(Ops, Ty, SE);
}
}
}
}
} else {
- // Without TargetData, just check for a SCEVFieldOffsetExpr of the
+ // Without TargetData, just check for an offsetof expression of the
// appropriate struct type.
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
- if (const SCEVFieldOffsetExpr *FO =
- dyn_cast<SCEVFieldOffsetExpr>(Ops[i]))
- if (FO->getStructType() == STy) {
- unsigned FieldNo = FO->getFieldNo();
- GepIndices.push_back(
- ConstantInt::get(Type::getInt32Ty(Ty->getContext()),
- FieldNo));
- ElTy = STy->getTypeAtIndex(FieldNo);
+ if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(Ops[i])) {
+ const Type *CTy;
+ Constant *FieldNo;
+ if (U->isOffsetOf(CTy, FieldNo) && CTy == STy) {
+ GepIndices.push_back(FieldNo);
+ ElTy =
+ STy->getTypeAtIndex(cast<ConstantInt>(FieldNo)->getZExtValue());
Ops[i] = SE.getConstant(Ty, 0);
AnyNonZeroIndices = true;
FoundFieldNo = true;
break;
}
+ }
}
// If no struct field offsets were found, tentatively assume that
// field zero was selected (since the zero offset would obviously
break;
}
- // If none of the operands were convertable to proper GEP indices, cast
+ // If none of the operands were convertible to proper GEP indices, cast
// the base to i8* and do an ugly getelementptr with that. It's still
// better than ptrtoint+arithmetic+inttoptr at least.
if (!AnyNonZeroIndices) {
if (IP != BlockBegin) {
--IP;
for (; ScanLimit; --IP, --ScanLimit) {
+ // Don't count dbg.value against the ScanLimit, to avoid perturbing the
+ // generated code.
+ if (isa<DbgInfoIntrinsic>(IP))
+ ScanLimit++;
if (IP->getOpcode() == Instruction::GetElementPtr &&
IP->getOperand(0) == V && IP->getOperand(1) == Idx)
return IP;
}
}
+ // Save the original insertion point so we can restore it when we're done.
+ BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
+ BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+
+ // Move the insertion point out of as many loops as we can.
+ while (const Loop *L = SE.LI->getLoopFor(Builder.GetInsertBlock())) {
+ if (!L->isLoopInvariant(V) || !L->isLoopInvariant(Idx)) break;
+ BasicBlock *Preheader = L->getLoopPreheader();
+ if (!Preheader) break;
+
+ // Ok, move up a level.
+ Builder.SetInsertPoint(Preheader, Preheader->getTerminator());
+ }
+
// Emit a GEP.
Value *GEP = Builder.CreateGEP(V, Idx, "uglygep");
- InsertedValues.insert(GEP);
+ rememberInstruction(GEP);
+
+ // Restore the original insert point.
+ if (SaveInsertBB)
+ restoreInsertPoint(SaveInsertBB, SaveInsertPt);
+
return GEP;
}
+ // Save the original insertion point so we can restore it when we're done.
+ BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
+ BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+
+ // Move the insertion point out of as many loops as we can.
+ while (const Loop *L = SE.LI->getLoopFor(Builder.GetInsertBlock())) {
+ if (!L->isLoopInvariant(V)) break;
+
+ bool AnyIndexNotLoopInvariant = false;
+ for (SmallVectorImpl<Value *>::const_iterator I = GepIndices.begin(),
+ E = GepIndices.end(); I != E; ++I)
+ if (!L->isLoopInvariant(*I)) {
+ AnyIndexNotLoopInvariant = true;
+ break;
+ }
+ if (AnyIndexNotLoopInvariant)
+ break;
+
+ BasicBlock *Preheader = L->getLoopPreheader();
+ if (!Preheader) break;
+
+ // Ok, move up a level.
+ Builder.SetInsertPoint(Preheader, Preheader->getTerminator());
+ }
+
// Insert a pretty getelementptr. Note that this GEP is not marked inbounds,
// because ScalarEvolution may have changed the address arithmetic to
// compute a value which is beyond the end of the allocated object.
- Value *GEP = Builder.CreateGEP(V,
+ Value *Casted = V;
+ if (V->getType() != PTy)
+ Casted = InsertNoopCastOfTo(Casted, PTy);
+ Value *GEP = Builder.CreateGEP(Casted,
GepIndices.begin(),
GepIndices.end(),
"scevgep");
Ops.push_back(SE.getUnknown(GEP));
- InsertedValues.insert(GEP);
+ rememberInstruction(GEP);
+
+ // Restore the original insert point.
+ if (SaveInsertBB)
+ restoreInsertPoint(SaveInsertBB, SaveInsertPt);
+
return expand(SE.getAddExpr(Ops));
}
+/// isNonConstantNegative - Return true if the specified scev is negated, but
+/// not a constant.
+static bool isNonConstantNegative(const SCEV *F) {
+ const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(F);
+ if (!Mul) return false;
+
+ // If there is a constant factor, it will be first.
+ const SCEVConstant *SC = dyn_cast<SCEVConstant>(Mul->getOperand(0));
+ if (!SC) return false;
+
+ // Return true if the value is negative, this matches things like (-42 * V).
+ return SC->getValue()->getValue().isNegative();
+}
+
+/// PickMostRelevantLoop - Given two loops pick the one that's most relevant for
+/// SCEV expansion. If they are nested, this is the most nested. If they are
+/// neighboring, pick the later.
+static const Loop *PickMostRelevantLoop(const Loop *A, const Loop *B,
+ DominatorTree &DT) {
+ if (!A) return B;
+ if (!B) return A;
+ if (A->contains(B)) return B;
+ if (B->contains(A)) return A;
+ if (DT.dominates(A->getHeader(), B->getHeader())) return B;
+ if (DT.dominates(B->getHeader(), A->getHeader())) return A;
+ return A; // Arbitrarily break the tie.
+}
+
+/// GetRelevantLoop - Get the most relevant loop associated with the given
+/// expression, according to PickMostRelevantLoop.
+static const Loop *GetRelevantLoop(const SCEV *S, LoopInfo &LI,
+ DominatorTree &DT) {
+ if (isa<SCEVConstant>(S))
+ return 0;
+ if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
+ if (const Instruction *I = dyn_cast<Instruction>(U->getValue()))
+ return LI.getLoopFor(I->getParent());
+ return 0;
+ }
+ if (const SCEVNAryExpr *N = dyn_cast<SCEVNAryExpr>(S)) {
+ const Loop *L = 0;
+ if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S))
+ L = AR->getLoop();
+ for (SCEVNAryExpr::op_iterator I = N->op_begin(), E = N->op_end();
+ I != E; ++I)
+ L = PickMostRelevantLoop(L, GetRelevantLoop(*I, LI, DT), DT);
+ return L;
+ }
+ if (const SCEVCastExpr *C = dyn_cast<SCEVCastExpr>(S))
+ return GetRelevantLoop(C->getOperand(), LI, DT);
+ if (const SCEVUDivExpr *D = dyn_cast<SCEVUDivExpr>(S))
+ return PickMostRelevantLoop(GetRelevantLoop(D->getLHS(), LI, DT),
+ GetRelevantLoop(D->getRHS(), LI, DT),
+ DT);
+ llvm_unreachable("Unexpected SCEV type!");
+}
+
+/// LoopCompare - Compare loops by PickMostRelevantLoop.
+class LoopCompare {
+ DominatorTree &DT;
+public:
+ explicit LoopCompare(DominatorTree &dt) : DT(dt) {}
+
+ bool operator()(std::pair<const Loop *, const SCEV *> LHS,
+ std::pair<const Loop *, const SCEV *> RHS) const {
+ // Compare loops with PickMostRelevantLoop.
+ if (LHS.first != RHS.first)
+ return PickMostRelevantLoop(LHS.first, RHS.first, DT) != LHS.first;
+
+ // If one operand is a non-constant negative and the other is not,
+ // put the non-constant negative on the right so that a sub can
+ // be used instead of a negate and add.
+ if (isNonConstantNegative(LHS.second)) {
+ if (!isNonConstantNegative(RHS.second))
+ return false;
+ } else if (isNonConstantNegative(RHS.second))
+ return true;
+
+ // Otherwise they are equivalent according to this comparison.
+ return false;
+ }
+};
+
Value *SCEVExpander::visitAddExpr(const SCEVAddExpr *S) {
- int NumOperands = S->getNumOperands();
const Type *Ty = SE.getEffectiveSCEVType(S->getType());
- // Find the index of an operand to start with. Choose the operand with
- // pointer type, if there is one, or the last operand otherwise.
- int PIdx = 0;
- for (; PIdx != NumOperands - 1; ++PIdx)
- if (isa<PointerType>(S->getOperand(PIdx)->getType())) break;
-
- // Expand code for the operand that we chose.
- Value *V = expand(S->getOperand(PIdx));
-
- // Turn things like ptrtoint+arithmetic+inttoptr into GEP. See the
- // comments on expandAddToGEP for details.
- if (const PointerType *PTy = dyn_cast<PointerType>(V->getType())) {
- // Take the operand at PIdx out of the list.
- const SmallVectorImpl<const SCEV *> &Ops = S->getOperands();
- SmallVector<const SCEV *, 8> NewOps;
- NewOps.insert(NewOps.end(), Ops.begin(), Ops.begin() + PIdx);
- NewOps.insert(NewOps.end(), Ops.begin() + PIdx + 1, Ops.end());
- // Make a GEP.
- return expandAddToGEP(NewOps.begin(), NewOps.end(), PTy, Ty, V);
- }
-
- // Otherwise, we'll expand the rest of the SCEVAddExpr as plain integer
- // arithmetic.
- V = InsertNoopCastOfTo(V, Ty);
-
- // Emit a bunch of add instructions
- for (int i = NumOperands-1; i >= 0; --i) {
- if (i == PIdx) continue;
- Value *W = expandCodeFor(S->getOperand(i), Ty);
- V = InsertBinop(Instruction::Add, V, W);
+ // Collect all the add operands in a loop, along with their associated loops.
+ // Iterate in reverse so that constants are emitted last, all else equal, and
+ // so that pointer operands are inserted first, which the code below relies on
+ // to form more involved GEPs.
+ SmallVector<std::pair<const Loop *, const SCEV *>, 8> OpsAndLoops;
+ for (std::reverse_iterator<SCEVAddExpr::op_iterator> I(S->op_end()),
+ E(S->op_begin()); I != E; ++I)
+ OpsAndLoops.push_back(std::make_pair(GetRelevantLoop(*I, *SE.LI, *SE.DT),
+ *I));
+
+ // Sort by loop. Use a stable sort so that constants follow non-constants and
+ // pointer operands precede non-pointer operands.
+ std::stable_sort(OpsAndLoops.begin(), OpsAndLoops.end(), LoopCompare(*SE.DT));
+
+ // Emit instructions to add all the operands. Hoist as much as possible
+ // out of loops, and form meaningful getelementptrs where possible.
+ Value *Sum = 0;
+ for (SmallVectorImpl<std::pair<const Loop *, const SCEV *> >::iterator
+ I = OpsAndLoops.begin(), E = OpsAndLoops.end(); I != E; ) {
+ const Loop *CurLoop = I->first;
+ const SCEV *Op = I->second;
+ if (!Sum) {
+ // This is the first operand. Just expand it.
+ Sum = expand(Op);
+ ++I;
+ } else if (const PointerType *PTy = dyn_cast<PointerType>(Sum->getType())) {
+ // The running sum expression is a pointer. Try to form a getelementptr
+ // at this level with that as the base.
+ SmallVector<const SCEV *, 4> NewOps;
+ for (; I != E && I->first == CurLoop; ++I)
+ NewOps.push_back(I->second);
+ Sum = expandAddToGEP(NewOps.begin(), NewOps.end(), PTy, Ty, Sum);
+ } else if (const PointerType *PTy = dyn_cast<PointerType>(Op->getType())) {
+ // The running sum is an integer, and there's a pointer at this level.
+ // Try to form a getelementptr.
+ SmallVector<const SCEV *, 4> NewOps;
+ NewOps.push_back(SE.getUnknown(Sum));
+ for (++I; I != E && I->first == CurLoop; ++I)
+ NewOps.push_back(I->second);
+ Sum = expandAddToGEP(NewOps.begin(), NewOps.end(), PTy, Ty, expand(Op));
+ } else if (isNonConstantNegative(Op)) {
+ // Instead of doing a negate and add, just do a subtract.
+ Value *W = expandCodeFor(SE.getNegativeSCEV(Op), Ty);
+ Sum = InsertNoopCastOfTo(Sum, Ty);
+ Sum = InsertBinop(Instruction::Sub, Sum, W);
+ ++I;
+ } else {
+ // A simple add.
+ Value *W = expandCodeFor(Op, Ty);
+ Sum = InsertNoopCastOfTo(Sum, Ty);
+ // Canonicalize a constant to the RHS.
+ if (isa<Constant>(Sum)) std::swap(Sum, W);
+ Sum = InsertBinop(Instruction::Add, Sum, W);
+ ++I;
+ }
}
- return V;
+
+ return Sum;
}
Value *SCEVExpander::visitMulExpr(const SCEVMulExpr *S) {
const Type *Ty = SE.getEffectiveSCEVType(S->getType());
- int FirstOp = 0; // Set if we should emit a subtract.
- if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getOperand(0)))
- if (SC->getValue()->isAllOnesValue())
- FirstOp = 1;
- int i = S->getNumOperands()-2;
- Value *V = expandCodeFor(S->getOperand(i+1), Ty);
-
- // Emit a bunch of multiply instructions
- for (; i >= FirstOp; --i) {
- Value *W = expandCodeFor(S->getOperand(i), Ty);
- V = InsertBinop(Instruction::Mul, V, W);
+ // Collect all the mul operands in a loop, along with their associated loops.
+ // Iterate in reverse so that constants are emitted last, all else equal.
+ SmallVector<std::pair<const Loop *, const SCEV *>, 8> OpsAndLoops;
+ for (std::reverse_iterator<SCEVMulExpr::op_iterator> I(S->op_end()),
+ E(S->op_begin()); I != E; ++I)
+ OpsAndLoops.push_back(std::make_pair(GetRelevantLoop(*I, *SE.LI, *SE.DT),
+ *I));
+
+ // Sort by loop. Use a stable sort so that constants follow non-constants.
+ std::stable_sort(OpsAndLoops.begin(), OpsAndLoops.end(), LoopCompare(*SE.DT));
+
+ // Emit instructions to mul all the operands. Hoist as much as possible
+ // out of loops.
+ Value *Prod = 0;
+ for (SmallVectorImpl<std::pair<const Loop *, const SCEV *> >::iterator
+ I = OpsAndLoops.begin(), E = OpsAndLoops.end(); I != E; ) {
+ const SCEV *Op = I->second;
+ if (!Prod) {
+ // This is the first operand. Just expand it.
+ Prod = expand(Op);
+ ++I;
+ } else if (Op->isAllOnesValue()) {
+ // Instead of doing a multiply by negative one, just do a negate.
+ Prod = InsertNoopCastOfTo(Prod, Ty);
+ Prod = InsertBinop(Instruction::Sub, Constant::getNullValue(Ty), Prod);
+ ++I;
+ } else {
+ // A simple mul.
+ Value *W = expandCodeFor(Op, Ty);
+ Prod = InsertNoopCastOfTo(Prod, Ty);
+ // Canonicalize a constant to the RHS.
+ if (isa<Constant>(Prod)) std::swap(Prod, W);
+ Prod = InsertBinop(Instruction::Mul, Prod, W);
+ ++I;
+ }
}
- // -1 * ... ---> 0 - ...
- if (FirstOp == 1)
- V = InsertBinop(Instruction::Sub, Constant::getNullValue(Ty), V);
- return V;
+ return Prod;
}
Value *SCEVExpander::visitUDivExpr(const SCEVUDivExpr *S) {
}
}
+/// getAddRecExprPHILiterally - Helper for expandAddRecExprLiterally. Expand
+/// the base addrec, which is the addrec without any non-loop-dominating
+/// values, and return the PHI.
+PHINode *
+SCEVExpander::getAddRecExprPHILiterally(const SCEVAddRecExpr *Normalized,
+ const Loop *L,
+ const Type *ExpandTy,
+ const Type *IntTy) {
+ // Reuse a previously-inserted PHI, if present.
+ for (BasicBlock::iterator I = L->getHeader()->begin();
+ PHINode *PN = dyn_cast<PHINode>(I); ++I)
+ if (SE.isSCEVable(PN->getType()) &&
+ (SE.getEffectiveSCEVType(PN->getType()) ==
+ SE.getEffectiveSCEVType(Normalized->getType())) &&
+ SE.getSCEV(PN) == Normalized)
+ if (BasicBlock *LatchBlock = L->getLoopLatch()) {
+ Instruction *IncV =
+ cast<Instruction>(PN->getIncomingValueForBlock(LatchBlock));
+
+ // Determine if this is a well-behaved chain of instructions leading
+ // back to the PHI. It probably will be, if we're scanning an inner
+ // loop already visited by LSR for example, but it wouldn't have
+ // to be.
+ do {
+ if (IncV->getNumOperands() == 0 || isa<PHINode>(IncV)) {
+ IncV = 0;
+ break;
+ }
+ // If any of the operands don't dominate the insert position, bail.
+ // Addrec operands are always loop-invariant, so this can only happen
+ // if there are instructions which haven't been hoisted.
+ for (User::op_iterator OI = IncV->op_begin()+1,
+ OE = IncV->op_end(); OI != OE; ++OI)
+ if (Instruction *OInst = dyn_cast<Instruction>(OI))
+ if (!SE.DT->dominates(OInst, IVIncInsertPos)) {
+ IncV = 0;
+ break;
+ }
+ if (!IncV)
+ break;
+ // Advance to the next instruction.
+ IncV = dyn_cast<Instruction>(IncV->getOperand(0));
+ if (!IncV)
+ break;
+ if (IncV->mayHaveSideEffects()) {
+ IncV = 0;
+ break;
+ }
+ } while (IncV != PN);
+
+ if (IncV) {
+ // Ok, the add recurrence looks usable.
+ // Remember this PHI, even in post-inc mode.
+ InsertedValues.insert(PN);
+ // Remember the increment.
+ IncV = cast<Instruction>(PN->getIncomingValueForBlock(LatchBlock));
+ rememberInstruction(IncV);
+ if (L == IVIncInsertLoop)
+ do {
+ if (SE.DT->dominates(IncV, IVIncInsertPos))
+ break;
+ // Make sure the increment is where we want it. But don't move it
+ // down past a potential existing post-inc user.
+ IncV->moveBefore(IVIncInsertPos);
+ IVIncInsertPos = IncV;
+ IncV = cast<Instruction>(IncV->getOperand(0));
+ } while (IncV != PN);
+ return PN;
+ }
+ }
+
+ // Save the original insertion point so we can restore it when we're done.
+ BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
+ BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
+
+ // Expand code for the start value.
+ Value *StartV = expandCodeFor(Normalized->getStart(), ExpandTy,
+ L->getHeader()->begin());
+
+ // Expand code for the step value. Insert instructions right before the
+ // terminator corresponding to the back-edge. Do this before creating the PHI
+ // so that PHI reuse code doesn't see an incomplete PHI. If the stride is
+ // negative, insert a sub instead of an add for the increment (unless it's a
+ // constant, because subtracts of constants are canonicalized to adds).
+ const SCEV *Step = Normalized->getStepRecurrence(SE);
+ bool isPointer = ExpandTy->isPointerTy();
+ bool isNegative = !isPointer && isNonConstantNegative(Step);
+ if (isNegative)
+ Step = SE.getNegativeSCEV(Step);
+ Value *StepV = expandCodeFor(Step, IntTy, L->getHeader()->begin());
+
+ // Create the PHI.
+ Builder.SetInsertPoint(L->getHeader(), L->getHeader()->begin());
+ PHINode *PN = Builder.CreatePHI(ExpandTy, "lsr.iv");
+ rememberInstruction(PN);
+
+ // Create the step instructions and populate the PHI.
+ BasicBlock *Header = L->getHeader();
+ for (pred_iterator HPI = pred_begin(Header), HPE = pred_end(Header);
+ HPI != HPE; ++HPI) {
+ BasicBlock *Pred = *HPI;
+
+ // Add a start value.
+ if (!L->contains(Pred)) {
+ PN->addIncoming(StartV, Pred);
+ continue;
+ }
+
+ // Create a step value and add it to the PHI. If IVIncInsertLoop is
+ // non-null and equal to the addrec's loop, insert the instructions
+ // at IVIncInsertPos.
+ Instruction *InsertPos = L == IVIncInsertLoop ?
+ IVIncInsertPos : Pred->getTerminator();
+ Builder.SetInsertPoint(InsertPos->getParent(), InsertPos);
+ Value *IncV;
+ // If the PHI is a pointer, use a GEP, otherwise use an add or sub.
+ if (isPointer) {
+ const PointerType *GEPPtrTy = cast<PointerType>(ExpandTy);
+ // If the step isn't constant, don't use an implicitly scaled GEP, because
+ // that would require a multiply inside the loop.
+ if (!isa<ConstantInt>(StepV))
+ GEPPtrTy = PointerType::get(Type::getInt1Ty(SE.getContext()),
+ GEPPtrTy->getAddressSpace());
+ const SCEV *const StepArray[1] = { SE.getSCEV(StepV) };
+ IncV = expandAddToGEP(StepArray, StepArray+1, GEPPtrTy, IntTy, PN);
+ if (IncV->getType() != PN->getType()) {
+ IncV = Builder.CreateBitCast(IncV, PN->getType(), "tmp");
+ rememberInstruction(IncV);
+ }
+ } else {
+ IncV = isNegative ?
+ Builder.CreateSub(PN, StepV, "lsr.iv.next") :
+ Builder.CreateAdd(PN, StepV, "lsr.iv.next");
+ rememberInstruction(IncV);
+ }
+ PN->addIncoming(IncV, Pred);
+ }
+
+ // Restore the original insert point.
+ if (SaveInsertBB)
+ restoreInsertPoint(SaveInsertBB, SaveInsertPt);
+
+ // Remember this PHI, even in post-inc mode.
+ InsertedValues.insert(PN);
+
+ return PN;
+}
+
+Value *SCEVExpander::expandAddRecExprLiterally(const SCEVAddRecExpr *S) {
+ const Type *STy = S->getType();
+ const Type *IntTy = SE.getEffectiveSCEVType(STy);
+ const Loop *L = S->getLoop();
+
+ // Determine a normalized form of this expression, which is the expression
+ // before any post-inc adjustment is made.
+ const SCEVAddRecExpr *Normalized = S;
+ if (L == PostIncLoop) {
+ const SCEV *Step = S->getStepRecurrence(SE);
+ Normalized = cast<SCEVAddRecExpr>(SE.getMinusSCEV(S, Step));
+ }
+
+ // Strip off any non-loop-dominating component from the addrec start.
+ const SCEV *Start = Normalized->getStart();
+ const SCEV *PostLoopOffset = 0;
+ if (!Start->properlyDominates(L->getHeader(), SE.DT)) {
+ PostLoopOffset = Start;
+ Start = SE.getIntegerSCEV(0, Normalized->getType());
+ Normalized =
+ cast<SCEVAddRecExpr>(SE.getAddRecExpr(Start,
+ Normalized->getStepRecurrence(SE),
+ Normalized->getLoop()));
+ }
+
+ // Strip off any non-loop-dominating component from the addrec step.
+ const SCEV *Step = Normalized->getStepRecurrence(SE);
+ const SCEV *PostLoopScale = 0;
+ if (!Step->hasComputableLoopEvolution(L) &&
+ !Step->dominates(L->getHeader(), SE.DT)) {
+ PostLoopScale = Step;
+ Step = SE.getIntegerSCEV(1, Normalized->getType());
+ Normalized =
+ cast<SCEVAddRecExpr>(SE.getAddRecExpr(Start, Step,
+ Normalized->getLoop()));
+ }
+
+ // Expand the core addrec. If we need post-loop scaling, force it to
+ // expand to an integer type to avoid the need for additional casting.
+ const Type *ExpandTy = PostLoopScale ? IntTy : STy;
+ PHINode *PN = getAddRecExprPHILiterally(Normalized, L, ExpandTy, IntTy);
+
+ // Accommodate post-inc mode, if necessary.
+ Value *Result;
+ if (L != PostIncLoop)
+ Result = PN;
+ else {
+ // In PostInc mode, use the post-incremented value.
+ BasicBlock *LatchBlock = L->getLoopLatch();
+ assert(LatchBlock && "PostInc mode requires a unique loop latch!");
+ Result = PN->getIncomingValueForBlock(LatchBlock);
+ }
+
+ // Re-apply any non-loop-dominating scale.
+ if (PostLoopScale) {
+ Result = InsertNoopCastOfTo(Result, IntTy);
+ Result = Builder.CreateMul(Result,
+ expandCodeFor(PostLoopScale, IntTy));
+ rememberInstruction(Result);
+ }
+
+ // Re-apply any non-loop-dominating offset.
+ if (PostLoopOffset) {
+ if (const PointerType *PTy = dyn_cast<PointerType>(ExpandTy)) {
+ const SCEV *const OffsetArray[1] = { PostLoopOffset };
+ Result = expandAddToGEP(OffsetArray, OffsetArray+1, PTy, IntTy, Result);
+ } else {
+ Result = InsertNoopCastOfTo(Result, IntTy);
+ Result = Builder.CreateAdd(Result,
+ expandCodeFor(PostLoopOffset, IntTy));
+ rememberInstruction(Result);
+ }
+ }
+
+ return Result;
+}
+
Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
+ if (!CanonicalMode) return expandAddRecExprLiterally(S);
+
const Type *Ty = SE.getEffectiveSCEVType(S->getType());
const Loop *L = S->getLoop();
PHINode *CanonicalIV = 0;
if (PHINode *PN = L->getCanonicalInductionVariable())
if (SE.isSCEVable(PN->getType()) &&
- isa<IntegerType>(SE.getEffectiveSCEVType(PN->getType())) &&
+ SE.getEffectiveSCEVType(PN->getType())->isIntegerTy() &&
SE.getTypeSizeInBits(PN->getType()) >= SE.getTypeSizeInBits(Ty))
CanonicalIV = PN;
if (CanonicalIV &&
SE.getTypeSizeInBits(CanonicalIV->getType()) >
SE.getTypeSizeInBits(Ty)) {
- const SmallVectorImpl<const SCEV *> &Ops = S->getOperands();
- SmallVector<const SCEV *, 4> NewOps(Ops.size());
- for (unsigned i = 0, e = Ops.size(); i != e; ++i)
- NewOps[i] = SE.getAnyExtendExpr(Ops[i], CanonicalIV->getType());
+ SmallVector<const SCEV *, 4> NewOps(S->getNumOperands());
+ for (unsigned i = 0, e = S->getNumOperands(); i != e; ++i)
+ NewOps[i] = SE.getAnyExtendExpr(S->op_begin()[i], CanonicalIV->getType());
Value *V = expand(SE.getAddRecExpr(NewOps, S->getLoop()));
BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
while (isa<PHINode>(NewInsertPt)) ++NewInsertPt;
V = expandCodeFor(SE.getTruncateExpr(SE.getUnknown(V), Ty), 0,
NewInsertPt);
- Builder.SetInsertPoint(SaveInsertBB, SaveInsertPt);
+ restoreInsertPoint(SaveInsertBB, SaveInsertPt);
return V;
}
// {X,+,F} --> X + {0,+,F}
if (!S->getStart()->isZero()) {
- const SmallVectorImpl<const SCEV *> &SOperands = S->getOperands();
- SmallVector<const SCEV *, 4> NewOps(SOperands.begin(), SOperands.end());
+ SmallVector<const SCEV *, 4> NewOps(S->op_begin(), S->op_end());
NewOps[0] = SE.getIntegerSCEV(0, Ty);
const SCEV *Rest = SE.getAddRecExpr(NewOps, L);
// specified loop.
BasicBlock *Header = L->getHeader();
PHINode *PN = PHINode::Create(Ty, "indvar", Header->begin());
- InsertedValues.insert(PN);
+ rememberInstruction(PN);
Constant *One = ConstantInt::get(Ty, 1);
for (pred_iterator HPI = pred_begin(Header), HPE = pred_end(Header);
// corresponding to the back-edge.
Instruction *Add = BinaryOperator::CreateAdd(PN, One, "indvar.next",
(*HPI)->getTerminator());
- InsertedValues.insert(Add);
+ rememberInstruction(Add);
PN->addIncoming(Add, *HPI);
} else {
PN->addIncoming(Constant::getNullValue(Ty), *HPI);
Value *V = expandCodeFor(S->getOperand(),
SE.getEffectiveSCEVType(S->getOperand()->getType()));
Value *I = Builder.CreateTrunc(V, Ty, "tmp");
- InsertedValues.insert(I);
+ rememberInstruction(I);
return I;
}
Value *V = expandCodeFor(S->getOperand(),
SE.getEffectiveSCEVType(S->getOperand()->getType()));
Value *I = Builder.CreateZExt(V, Ty, "tmp");
- InsertedValues.insert(I);
+ rememberInstruction(I);
return I;
}
Value *V = expandCodeFor(S->getOperand(),
SE.getEffectiveSCEVType(S->getOperand()->getType()));
Value *I = Builder.CreateSExt(V, Ty, "tmp");
- InsertedValues.insert(I);
+ rememberInstruction(I);
return I;
}
}
Value *RHS = expandCodeFor(S->getOperand(i), Ty);
Value *ICmp = Builder.CreateICmpSGT(LHS, RHS, "tmp");
- InsertedValues.insert(ICmp);
+ rememberInstruction(ICmp);
Value *Sel = Builder.CreateSelect(ICmp, LHS, RHS, "smax");
- InsertedValues.insert(Sel);
+ rememberInstruction(Sel);
LHS = Sel;
}
// In the case of mixed integer and pointer types, cast the
}
Value *RHS = expandCodeFor(S->getOperand(i), Ty);
Value *ICmp = Builder.CreateICmpUGT(LHS, RHS, "tmp");
- InsertedValues.insert(ICmp);
+ rememberInstruction(ICmp);
Value *Sel = Builder.CreateSelect(ICmp, LHS, RHS, "umax");
- InsertedValues.insert(Sel);
+ rememberInstruction(Sel);
LHS = Sel;
}
// In the case of mixed integer and pointer types, cast the
return LHS;
}
-Value *SCEVExpander::visitFieldOffsetExpr(const SCEVFieldOffsetExpr *S) {
- return ConstantExpr::getOffsetOf(S->getStructType(), S->getFieldNo());
-}
-
-Value *SCEVExpander::visitAllocSizeExpr(const SCEVAllocSizeExpr *S) {
- return ConstantExpr::getSizeOf(S->getAllocType());
-}
-
Value *SCEVExpander::expandCodeFor(const SCEV *SH, const Type *Ty) {
// Expand the code for this SCEV.
Value *V = expand(SH);
L = L->getParentLoop())
if (S->isLoopInvariant(L)) {
if (!L) break;
- if (BasicBlock *Preheader = L->getLoopPreheader())
+ if (BasicBlock *Preheader = L->getLoopPreheader()) {
InsertPt = Preheader->getTerminator();
+ BasicBlock::iterator IP = InsertPt;
+ // Back past any debug info instructions. Sometimes we inserted
+ // something earlier before debug info but after any real instructions.
+ // This should behave the same as if debug info was not present.
+ while (IP != Preheader->begin()) {
+ --IP;
+ if (!isa<DbgInfoIntrinsic>(IP))
+ break;
+ InsertPt = IP;
+ }
+ }
} else {
// If the SCEV is computable at this level, insert it into the header
// after the PHIs (and after any other instructions that we've inserted
// there) so that it is guaranteed to dominate any user inside the loop.
- if (L && S->hasComputableLoopEvolution(L))
+ if (L && S->hasComputableLoopEvolution(L) && L != PostIncLoop)
InsertPt = L->getHeader()->getFirstNonPHI();
+ while (isa<DbgInfoIntrinsic>(InsertPt))
+ InsertPt = llvm::next(BasicBlock::iterator(InsertPt));
while (isInsertedInstruction(InsertPt))
InsertPt = llvm::next(BasicBlock::iterator(InsertPt));
break;
Value *V = visit(S);
// Remember the expanded value for this SCEV at this location.
- InsertedExpressions[std::make_pair(S, InsertPt)] = V;
+ if (!PostIncLoop)
+ InsertedExpressions[std::make_pair(S, InsertPt)] = V;
- Builder.SetInsertPoint(SaveInsertBB, SaveInsertPt);
+ restoreInsertPoint(SaveInsertBB, SaveInsertPt);
return V;
}
+void SCEVExpander::rememberInstruction(Value *I) {
+ if (!PostIncLoop)
+ InsertedValues.insert(I);
+
+ // If we just claimed an existing instruction and that instruction had
+ // been the insert point, adjust the insert point forward so that
+ // subsequently inserted code will be dominated.
+ if (Builder.GetInsertPoint() == I) {
+ BasicBlock::iterator It = cast<Instruction>(I);
+ do { ++It; } while (isInsertedInstruction(It));
+ Builder.SetInsertPoint(Builder.GetInsertBlock(), It);
+ }
+}
+
+void SCEVExpander::restoreInsertPoint(BasicBlock *BB, BasicBlock::iterator I) {
+ // If we acquired more instructions since the old insert point was saved,
+ // advance past them.
+ while (isInsertedInstruction(I)) ++I;
+
+ Builder.SetInsertPoint(BB, I);
+}
+
/// getOrInsertCanonicalInductionVariable - This method returns the
/// canonical induction variable of the specified type for the specified
/// loop (inserting one if there is none). A canonical induction variable
Value *
SCEVExpander::getOrInsertCanonicalInductionVariable(const Loop *L,
const Type *Ty) {
- assert(Ty->isInteger() && "Can only insert integer induction variables!");
+ assert(Ty->isIntegerTy() && "Can only insert integer induction variables!");
const SCEV *H = SE.getAddRecExpr(SE.getIntegerSCEV(0, Ty),
SE.getIntegerSCEV(1, Ty), L);
BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
Value *V = expandCodeFor(H, 0, L->getHeader()->begin());
if (SaveInsertBB)
- Builder.SetInsertPoint(SaveInsertBB, SaveInsertPt);
+ restoreInsertPoint(SaveInsertBB, SaveInsertPt);
return V;
}
projects / oota-llvm.git / blobdiff