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 we haven't found this binop, insert it.
Value *BO = Builder.CreateBinOp(Opcode, LHS, RHS, "tmp");
- InsertedValues.insert(BO);
+ rememberInstruction(BO);
return BO;
}
/// http://llvm.org/docs/LangRef.html#pointeraliasing
/// for details.
///
-/// Design note: The correctness of using getelmeentptr here depends on
+/// Design note: The correctness of using getelementptr here depends on
/// ScalarEvolution not recognizing inttoptr and ptrtoint operators, as
/// they may introduce pointer arithmetic which may not be safely converted
/// into getelementptr.
// without the other.
SplitAddRecs(Ops, Ty, SE);
- // Decend down the pointer's type and attempt to convert the other
+ // Descend down the pointer's type and attempt to convert the other
// operands into GEP indices, at each level. The first index in a GEP
// indexes into the array implied by the pointer operand; the rest of
// the indices index into the element or field type selected by the
if (!AnyNonZeroIndices) {
// Cast the base to i8*.
V = InsertNoopCastOfTo(V,
- Type::getInt8Ty(Ty->getContext())->getPointerTo(PTy->getAddressSpace()));
+ Type::getInt8PtrTy(Ty->getContext(), PTy->getAddressSpace()));
// Expand the operands for a plain byte offset.
Value *Idx = expandCodeFor(SE.getAddExpr(Ops), Ty);
// Emit a GEP.
Value *GEP = Builder.CreateGEP(V, Idx, "uglygep");
- InsertedValues.insert(GEP);
+ rememberInstruction(GEP);
return GEP;
}
// 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);
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();
+}
+
Value *SCEVExpander::visitAddExpr(const SCEVAddExpr *S) {
int NumOperands = S->getNumOperands();
const Type *Ty = SE.getEffectiveSCEVType(S->getType());
// 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);
+ const SCEV *Op = S->getOperand(i);
+ if (isNonConstantNegative(Op)) {
+ Value *W = expandCodeFor(SE.getNegativeSCEV(Op), Ty);
+ V = InsertBinop(Instruction::Sub, V, W);
+ } else {
+ Value *W = expandCodeFor(Op, Ty);
+ V = InsertBinop(Instruction::Add, V, W);
+ }
}
return V;
}
}
}
+/// 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 (isInsertedInstruction(PN) && SE.getSCEV(PN) == Normalized)
+ 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 = isa<PointerType>(ExpandTy);
+ 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)
+ Builder.SetInsertPoint(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);
+
+ // Accomodate 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 = 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 = 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();
if (CanonicalIV &&
SE.getTypeSizeInBits(CanonicalIV->getType()) >
SE.getTypeSizeInBits(Ty)) {
- const SCEV *Start = SE.getAnyExtendExpr(S->getStart(),
- CanonicalIV->getType());
- const SCEV *Step = SE.getAnyExtendExpr(S->getStepRecurrence(SE),
- CanonicalIV->getType());
- Value *V = expand(SE.getAddRecExpr(Start, Step, S->getLoop()));
+ 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());
+ Value *V = expand(SE.getAddRecExpr(NewOps, S->getLoop()));
BasicBlock *SaveInsertBB = Builder.GetInsertBlock();
BasicBlock::iterator SaveInsertPt = Builder.GetInsertPoint();
BasicBlock::iterator NewInsertPt =
- next(BasicBlock::iterator(cast<Instruction>(V)));
+ llvm::next(BasicBlock::iterator(cast<Instruction>(V)));
while (isa<PHINode>(NewInsertPt)) ++NewInsertPt;
V = expandCodeFor(SE.getTruncateExpr(SE.getUnknown(V), Ty), 0,
NewInsertPt);
// Create and insert the PHI node for the induction variable in the
// specified loop.
BasicBlock *Header = L->getHeader();
- BasicBlock *Preheader = L->getLoopPreheader();
PHINode *PN = PHINode::Create(Ty, "indvar", Header->begin());
- InsertedValues.insert(PN);
- PN->addIncoming(Constant::getNullValue(Ty), Preheader);
+ rememberInstruction(PN);
- pred_iterator HPI = pred_begin(Header);
- assert(HPI != pred_end(Header) && "Loop with zero preds???");
- if (!L->contains(*HPI)) ++HPI;
- assert(HPI != pred_end(Header) && L->contains(*HPI) &&
- "No backedge in loop?");
-
- // Insert a unit add instruction right before the terminator corresponding
- // to the back-edge.
Constant *One = ConstantInt::get(Ty, 1);
- Instruction *Add = BinaryOperator::CreateAdd(PN, One, "indvar.next",
- (*HPI)->getTerminator());
- InsertedValues.insert(Add);
-
- pred_iterator PI = pred_begin(Header);
- if (*PI == Preheader)
- ++PI;
- PN->addIncoming(Add, *PI);
- return PN;
+ for (pred_iterator HPI = pred_begin(Header), HPE = pred_end(Header);
+ HPI != HPE; ++HPI)
+ if (L->contains(*HPI)) {
+ // Insert a unit add instruction right before the terminator
+ // corresponding to the back-edge.
+ Instruction *Add = BinaryOperator::CreateAdd(PN, One, "indvar.next",
+ (*HPI)->getTerminator());
+ rememberInstruction(Add);
+ PN->addIncoming(Add, *HPI);
+ } else {
+ PN->addIncoming(Constant::getNullValue(Ty), *HPI);
+ }
}
// {0,+,F} --> {0,+,1} * F
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
if (L && S->hasComputableLoopEvolution(L))
InsertPt = L->getHeader()->getFirstNonPHI();
while (isInsertedInstruction(InsertPt))
- InsertPt = next(BasicBlock::iterator(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);
return V;
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