#include "llvm/Operator.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Assembly/Writer.h"
"derived loop"),
cl::init(100));
-INITIALIZE_PASS(ScalarEvolution, "scalar-evolution",
- "Scalar Evolution Analysis", false, true);
+INITIALIZE_PASS_BEGIN(ScalarEvolution, "scalar-evolution",
+ "Scalar Evolution Analysis", false, true)
+INITIALIZE_PASS_DEPENDENCY(LoopInfo)
+INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_PASS_END(ScalarEvolution, "scalar-evolution",
+ "Scalar Evolution Analysis", false, true)
char ScalarEvolution::ID = 0;
//===----------------------------------------------------------------------===//
SCEVCouldNotCompute::SCEVCouldNotCompute() :
SCEV(FoldingSetNodeIDRef(), scCouldNotCompute) {}
-bool SCEVCouldNotCompute::isLoopInvariant(const Loop *L) const {
- llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
- return false;
-}
-
const Type *SCEVCouldNotCompute::getType() const {
llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
return 0;
}
-bool SCEVCouldNotCompute::hasComputableLoopEvolution(const Loop *L) const {
- llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
- return false;
-}
-
bool SCEVCouldNotCompute::hasOperand(const SCEV *) const {
llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
return false;
return true;
}
-bool SCEVNAryExpr::isLoopInvariant(const Loop *L) const {
- for (op_iterator I = op_begin(), E = op_end(); I != E; ++I)
- if (!(*I)->isLoopInvariant(L))
- return false;
- return true;
-}
-
-// hasComputableLoopEvolution - N-ary expressions have computable loop
-// evolutions iff they have at least one operand that varies with the loop,
-// but that all varying operands are computable.
-bool SCEVNAryExpr::hasComputableLoopEvolution(const Loop *L) const {
- bool HasVarying = false;
- for (op_iterator I = op_begin(), E = op_end(); I != E; ++I) {
- const SCEV *S = *I;
- if (!S->isLoopInvariant(L)) {
- if (S->hasComputableLoopEvolution(L))
- HasVarying = true;
- else
- return false;
- }
- }
- return HasVarying;
-}
-
bool SCEVNAryExpr::hasOperand(const SCEV *O) const {
for (op_iterator I = op_begin(), E = op_end(); I != E; ++I) {
const SCEV *S = *I;
return RHS->getType();
}
-bool SCEVAddRecExpr::isLoopInvariant(const Loop *QueryLoop) const {
- // Add recurrences are never invariant in the function-body (null loop).
- if (!QueryLoop)
- return false;
-
- // This recurrence is variant w.r.t. QueryLoop if QueryLoop contains L.
- if (QueryLoop->contains(L))
- return false;
-
- // This recurrence is invariant w.r.t. QueryLoop if L contains QueryLoop.
- if (L->contains(QueryLoop))
- return true;
-
- // This recurrence is variant w.r.t. QueryLoop if any of its operands
- // are variant.
- for (op_iterator I = op_begin(), E = op_end(); I != E; ++I)
- if (!(*I)->isLoopInvariant(QueryLoop))
- return false;
-
- // Otherwise it's loop-invariant.
- return true;
-}
-
bool
SCEVAddRecExpr::dominates(BasicBlock *BB, DominatorTree *DT) const {
return DT->dominates(L->getHeader(), BB) &&
}
void SCEVUnknown::deleted() {
- // Clear this SCEVUnknown from ValuesAtScopes.
+ // Clear this SCEVUnknown from various maps.
SE->ValuesAtScopes.erase(this);
+ SE->UnsignedRanges.erase(this);
+ SE->SignedRanges.erase(this);
// Remove this SCEVUnknown from the uniquing map.
SE->UniqueSCEVs.RemoveNode(this);
}
void SCEVUnknown::allUsesReplacedWith(Value *New) {
- // Clear this SCEVUnknown from ValuesAtScopes.
+ // Clear this SCEVUnknown from various maps.
SE->ValuesAtScopes.erase(this);
+ SE->UnsignedRanges.erase(this);
+ SE->SignedRanges.erase(this);
// Remove this SCEVUnknown from the uniquing map.
SE->UniqueSCEVs.RemoveNode(this);
setValPtr(New);
}
-bool SCEVUnknown::isLoopInvariant(const Loop *L) const {
- // All non-instruction values are loop invariant. All instructions are loop
- // invariant if they are not contained in the specified loop.
- // Instructions are never considered invariant in the function body
- // (null loop) because they are defined within the "loop".
- if (Instruction *I = dyn_cast<Instruction>(getValue()))
- return L && !L->contains(I);
- return true;
-}
-
bool SCEVUnknown::dominates(BasicBlock *BB, DominatorTree *DT) const {
if (Instruction *I = dyn_cast<Instruction>(getValue()))
return DT->dominates(I->getParent(), BB);
if (Ops.size() == 2) {
// This is the common case, which also happens to be trivially simple.
// Special case it.
- if (SCEVComplexityCompare(LI)(Ops[1], Ops[0]))
- std::swap(Ops[0], Ops[1]);
+ const SCEV *&LHS = Ops[0], *&RHS = Ops[1];
+ if (SCEVComplexityCompare(LI)(RHS, LHS))
+ std::swap(LHS, RHS);
return;
}
}
// Check this multiply against other multiplies being added together.
- bool AnyFold = false;
for (unsigned OtherMulIdx = Idx+1;
OtherMulIdx < Ops.size() && isa<SCEVMulExpr>(Ops[OtherMulIdx]);
++OtherMulIdx) {
const SCEV *InnerMulSum = getAddExpr(InnerMul1,InnerMul2);
const SCEV *OuterMul = getMulExpr(MulOpSCEV, InnerMulSum);
if (Ops.size() == 2) return OuterMul;
- Ops[Idx] = OuterMul;
- Ops.erase(Ops.begin()+OtherMulIdx);
- OtherMulIdx = Idx;
- AnyFold = true;
+ Ops.erase(Ops.begin()+Idx);
+ Ops.erase(Ops.begin()+OtherMulIdx-1);
+ Ops.push_back(OuterMul);
+ return getAddExpr(Ops);
}
}
- if (AnyFold)
- return getAddExpr(Ops);
}
}
const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]);
const Loop *AddRecLoop = AddRec->getLoop();
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
- if (Ops[i]->isLoopInvariant(AddRecLoop)) {
+ if (isLoopInvariant(Ops[i], AddRecLoop)) {
LIOps.push_back(Ops[i]);
Ops.erase(Ops.begin()+i);
--i; --e;
// already have one, otherwise create a new one.
FoldingSetNodeID ID;
ID.AddInteger(scAddExpr);
- ID.AddInteger(Ops.size());
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
ID.AddPointer(Ops[i]);
void *IP = 0;
const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]);
const Loop *AddRecLoop = AddRec->getLoop();
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
- if (Ops[i]->isLoopInvariant(AddRecLoop)) {
+ if (isLoopInvariant(Ops[i], AddRecLoop)) {
LIOps.push_back(Ops[i]);
Ops.erase(Ops.begin()+i);
--i; --e;
// there are multiple AddRec's with the same loop induction variable being
// multiplied together. If so, we can fold them.
for (unsigned OtherIdx = Idx+1;
- OtherIdx < Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);++OtherIdx)
- if (OtherIdx != Idx) {
- const SCEVAddRecExpr *OtherAddRec = cast<SCEVAddRecExpr>(Ops[OtherIdx]);
- if (AddRecLoop == OtherAddRec->getLoop()) {
- // F * G --> {A,+,B} * {C,+,D} --> {A*C,+,F*D + G*B + B*D}
- const SCEVAddRecExpr *F = AddRec, *G = OtherAddRec;
- const SCEV *NewStart = getMulExpr(F->getStart(), G->getStart());
- const SCEV *B = F->getStepRecurrence(*this);
- const SCEV *D = G->getStepRecurrence(*this);
- const SCEV *NewStep = getAddExpr(getMulExpr(F, D),
- getMulExpr(G, B),
- getMulExpr(B, D));
- const SCEV *NewAddRec = getAddRecExpr(NewStart, NewStep,
- F->getLoop());
- if (Ops.size() == 2) return NewAddRec;
-
- Ops.erase(Ops.begin()+Idx);
- Ops.erase(Ops.begin()+OtherIdx-1);
- Ops.push_back(NewAddRec);
- return getMulExpr(Ops);
- }
+ OtherIdx < Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
+ ++OtherIdx)
+ if (AddRecLoop == cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()) {
+ // F * G, where F = {A,+,B}<L> and G = {C,+,D}<L> -->
+ // {A*C,+,F*D + G*B + B*D}<L>
+ for (; OtherIdx != Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
+ ++OtherIdx)
+ if (const SCEVAddRecExpr *OtherAddRec =
+ dyn_cast<SCEVAddRecExpr>(Ops[OtherIdx]))
+ if (OtherAddRec->getLoop() == AddRecLoop) {
+ const SCEVAddRecExpr *F = AddRec, *G = OtherAddRec;
+ const SCEV *NewStart = getMulExpr(F->getStart(), G->getStart());
+ const SCEV *B = F->getStepRecurrence(*this);
+ const SCEV *D = G->getStepRecurrence(*this);
+ const SCEV *NewStep = getAddExpr(getMulExpr(F, D),
+ getMulExpr(G, B),
+ getMulExpr(B, D));
+ const SCEV *NewAddRec = getAddRecExpr(NewStart, NewStep,
+ F->getLoop());
+ if (Ops.size() == 2) return NewAddRec;
+ Ops[Idx] = AddRec = cast<SCEVAddRecExpr>(NewAddRec);
+ Ops.erase(Ops.begin() + OtherIdx); --OtherIdx;
+ }
+ return getMulExpr(Ops);
}
// Otherwise couldn't fold anything into this recurrence. Move onto the
// already have one, otherwise create a new one.
FoldingSetNodeID ID;
ID.AddInteger(scMulExpr);
- ID.AddInteger(Ops.size());
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
ID.AddPointer(Ops[i]);
void *IP = 0;
for (unsigned i = 1, e = Operands.size(); i != e; ++i)
assert(getEffectiveSCEVType(Operands[i]->getType()) == ETy &&
"SCEVAddRecExpr operand types don't match!");
+ for (unsigned i = 0, e = Operands.size(); i != e; ++i)
+ assert(isLoopInvariant(Operands[i], L) &&
+ "SCEVAddRecExpr operand is not loop-invariant!");
#endif
if (Operands.back()->isZero()) {
// requirement.
bool AllInvariant = true;
for (unsigned i = 0, e = Operands.size(); i != e; ++i)
- if (!Operands[i]->isLoopInvariant(L)) {
+ if (!isLoopInvariant(Operands[i], L)) {
AllInvariant = false;
break;
}
NestedOperands[0] = getAddRecExpr(Operands, L);
AllInvariant = true;
for (unsigned i = 0, e = NestedOperands.size(); i != e; ++i)
- if (!NestedOperands[i]->isLoopInvariant(NestedLoop)) {
+ if (!isLoopInvariant(NestedOperands[i], NestedLoop)) {
AllInvariant = false;
break;
}
// already have one, otherwise create a new one.
FoldingSetNodeID ID;
ID.AddInteger(scAddRecExpr);
- ID.AddInteger(Operands.size());
for (unsigned i = 0, e = Operands.size(); i != e; ++i)
ID.AddPointer(Operands[i]);
ID.AddPointer(L);
// already have one, otherwise create a new one.
FoldingSetNodeID ID;
ID.AddInteger(scSMaxExpr);
- ID.AddInteger(Ops.size());
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
ID.AddPointer(Ops[i]);
void *IP = 0;
// already have one, otherwise create a new one.
FoldingSetNodeID ID;
ID.AddInteger(scUMaxExpr);
- ID.AddInteger(Ops.size());
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
ID.AddPointer(Ops[i]);
void *IP = 0;
ValueExprMapType::iterator It =
ValueExprMap.find(static_cast<Value *>(I));
if (It != ValueExprMap.end()) {
+ const SCEV *Old = It->second;
+
// Short-circuit the def-use traversal if the symbolic name
// ceases to appear in expressions.
- if (It->second != SymName && !It->second->hasOperand(SymName))
+ if (Old != SymName && !Old->hasOperand(SymName))
continue;
// SCEVUnknown for a PHI either means that it has an unrecognized
// updates on its own when it gets to that point. In the third, we do
// want to forget the SCEVUnknown.
if (!isa<PHINode>(I) ||
- !isa<SCEVUnknown>(It->second) ||
- (I != PN && It->second == SymName)) {
- ValuesAtScopes.erase(It->second);
+ !isa<SCEVUnknown>(Old) ||
+ (I != PN && Old == SymName)) {
+ ValuesAtScopes.erase(Old);
+ UnsignedRanges.erase(Old);
+ SignedRanges.erase(Old);
ValueExprMap.erase(It);
}
}
// This is not a valid addrec if the step amount is varying each
// loop iteration, but is not itself an addrec in this loop.
- if (Accum->isLoopInvariant(L) ||
+ if (isLoopInvariant(Accum, L) ||
(isa<SCEVAddRecExpr>(Accum) &&
cast<SCEVAddRecExpr>(Accum)->getLoop() == L)) {
bool HasNUW = false;
// Since the no-wrap flags are on the increment, they apply to the
// post-incremented value as well.
- if (Accum->isLoopInvariant(L))
+ if (isLoopInvariant(Accum, L))
(void)getAddRecExpr(getAddExpr(StartVal, Accum),
Accum, L, HasNUW, HasNSW);
// PHI's incoming blocks are in a different loop, in which case doing so
// risks breaking LCSSA form. Instcombine would normally zap these, but
// it doesn't have DominatorTree information, so it may miss cases.
- if (Value *V = PN->hasConstantValue(DT)) {
- bool AllSameLoop = true;
- Loop *PNLoop = LI->getLoopFor(PN->getParent());
- for (size_t i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
- if (LI->getLoopFor(PN->getIncomingBlock(i)) != PNLoop) {
- AllSameLoop = false;
- break;
- }
- if (AllSameLoop)
+ if (Value *V = SimplifyInstruction(PN, TD, DT)) {
+ Instruction *I = dyn_cast<Instruction>(V);
+ // Only instructions are problematic for preserving LCSSA form.
+ if (!I)
return getSCEV(V);
+
+ // If the instruction is not defined in a loop, then it can be used freely.
+ Loop *ILoop = LI->getLoopFor(I->getParent());
+ if (!ILoop)
+ return getSCEV(I);
+
+ // If the instruction is defined in the same loop as the phi node, or in a
+ // loop that contains the phi node loop as an inner loop, then using it as
+ // a replacement for the phi node will not break LCSSA form.
+ Loop *PNLoop = LI->getLoopFor(PN->getParent());
+ if (ILoop->contains(PNLoop))
+ return getSCEV(I);
}
// If it's not a loop phi, we can't handle it yet.
///
ConstantRange
ScalarEvolution::getUnsignedRange(const SCEV *S) {
+ // See if we've computed this range already.
+ DenseMap<const SCEV *, ConstantRange>::iterator I = UnsignedRanges.find(S);
+ if (I != UnsignedRanges.end())
+ return I->second;
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S))
- return ConstantRange(C->getValue()->getValue());
+ return setUnsignedRange(C, ConstantRange(C->getValue()->getValue()));
unsigned BitWidth = getTypeSizeInBits(S->getType());
ConstantRange ConservativeResult(BitWidth, /*isFullSet=*/true);
ConstantRange X = getUnsignedRange(Add->getOperand(0));
for (unsigned i = 1, e = Add->getNumOperands(); i != e; ++i)
X = X.add(getUnsignedRange(Add->getOperand(i)));
- return ConservativeResult.intersectWith(X);
+ return setUnsignedRange(Add, ConservativeResult.intersectWith(X));
}
if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(S)) {
ConstantRange X = getUnsignedRange(Mul->getOperand(0));
for (unsigned i = 1, e = Mul->getNumOperands(); i != e; ++i)
X = X.multiply(getUnsignedRange(Mul->getOperand(i)));
- return ConservativeResult.intersectWith(X);
+ return setUnsignedRange(Mul, ConservativeResult.intersectWith(X));
}
if (const SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(S)) {
ConstantRange X = getUnsignedRange(SMax->getOperand(0));
for (unsigned i = 1, e = SMax->getNumOperands(); i != e; ++i)
X = X.smax(getUnsignedRange(SMax->getOperand(i)));
- return ConservativeResult.intersectWith(X);
+ return setUnsignedRange(SMax, ConservativeResult.intersectWith(X));
}
if (const SCEVUMaxExpr *UMax = dyn_cast<SCEVUMaxExpr>(S)) {
ConstantRange X = getUnsignedRange(UMax->getOperand(0));
for (unsigned i = 1, e = UMax->getNumOperands(); i != e; ++i)
X = X.umax(getUnsignedRange(UMax->getOperand(i)));
- return ConservativeResult.intersectWith(X);
+ return setUnsignedRange(UMax, ConservativeResult.intersectWith(X));
}
if (const SCEVUDivExpr *UDiv = dyn_cast<SCEVUDivExpr>(S)) {
ConstantRange X = getUnsignedRange(UDiv->getLHS());
ConstantRange Y = getUnsignedRange(UDiv->getRHS());
- return ConservativeResult.intersectWith(X.udiv(Y));
+ return setUnsignedRange(UDiv, ConservativeResult.intersectWith(X.udiv(Y)));
}
if (const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(S)) {
ConstantRange X = getUnsignedRange(ZExt->getOperand());
- return ConservativeResult.intersectWith(X.zeroExtend(BitWidth));
+ return setUnsignedRange(ZExt,
+ ConservativeResult.intersectWith(X.zeroExtend(BitWidth)));
}
if (const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(S)) {
ConstantRange X = getUnsignedRange(SExt->getOperand());
- return ConservativeResult.intersectWith(X.signExtend(BitWidth));
+ return setUnsignedRange(SExt,
+ ConservativeResult.intersectWith(X.signExtend(BitWidth)));
}
if (const SCEVTruncateExpr *Trunc = dyn_cast<SCEVTruncateExpr>(S)) {
ConstantRange X = getUnsignedRange(Trunc->getOperand());
- return ConservativeResult.intersectWith(X.truncate(BitWidth));
+ return setUnsignedRange(Trunc,
+ ConservativeResult.intersectWith(X.truncate(BitWidth)));
}
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) {
ConstantRange ExtEndRange = EndRange.zextOrTrunc(BitWidth*2+1);
if (ExtStartRange.add(ExtMaxBECountRange.multiply(ExtStepRange)) !=
ExtEndRange)
- return ConservativeResult;
+ return setUnsignedRange(AddRec, ConservativeResult);
APInt Min = APIntOps::umin(StartRange.getUnsignedMin(),
EndRange.getUnsignedMin());
APInt Max = APIntOps::umax(StartRange.getUnsignedMax(),
EndRange.getUnsignedMax());
if (Min.isMinValue() && Max.isMaxValue())
- return ConservativeResult;
- return ConservativeResult.intersectWith(ConstantRange(Min, Max+1));
+ return setUnsignedRange(AddRec, ConservativeResult);
+ return setUnsignedRange(AddRec,
+ ConservativeResult.intersectWith(ConstantRange(Min, Max+1)));
}
}
- return ConservativeResult;
+ return setUnsignedRange(AddRec, ConservativeResult);
}
if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
APInt Zeros(BitWidth, 0), Ones(BitWidth, 0);
ComputeMaskedBits(U->getValue(), Mask, Zeros, Ones, TD);
if (Ones == ~Zeros + 1)
- return ConservativeResult;
- return ConservativeResult.intersectWith(ConstantRange(Ones, ~Zeros + 1));
+ return setUnsignedRange(U, ConservativeResult);
+ return setUnsignedRange(U,
+ ConservativeResult.intersectWith(ConstantRange(Ones, ~Zeros + 1)));
}
- return ConservativeResult;
+ return setUnsignedRange(S, ConservativeResult);
}
/// getSignedRange - Determine the signed range for a particular SCEV.
///
ConstantRange
ScalarEvolution::getSignedRange(const SCEV *S) {
+ DenseMap<const SCEV *, ConstantRange>::iterator I = SignedRanges.find(S);
+ if (I != SignedRanges.end())
+ return I->second;
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S))
- return ConstantRange(C->getValue()->getValue());
+ return setSignedRange(C, ConstantRange(C->getValue()->getValue()));
unsigned BitWidth = getTypeSizeInBits(S->getType());
ConstantRange ConservativeResult(BitWidth, /*isFullSet=*/true);
ConstantRange X = getSignedRange(Add->getOperand(0));
for (unsigned i = 1, e = Add->getNumOperands(); i != e; ++i)
X = X.add(getSignedRange(Add->getOperand(i)));
- return ConservativeResult.intersectWith(X);
+ return setSignedRange(Add, ConservativeResult.intersectWith(X));
}
if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(S)) {
ConstantRange X = getSignedRange(Mul->getOperand(0));
for (unsigned i = 1, e = Mul->getNumOperands(); i != e; ++i)
X = X.multiply(getSignedRange(Mul->getOperand(i)));
- return ConservativeResult.intersectWith(X);
+ return setSignedRange(Mul, ConservativeResult.intersectWith(X));
}
if (const SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(S)) {
ConstantRange X = getSignedRange(SMax->getOperand(0));
for (unsigned i = 1, e = SMax->getNumOperands(); i != e; ++i)
X = X.smax(getSignedRange(SMax->getOperand(i)));
- return ConservativeResult.intersectWith(X);
+ return setSignedRange(SMax, ConservativeResult.intersectWith(X));
}
if (const SCEVUMaxExpr *UMax = dyn_cast<SCEVUMaxExpr>(S)) {
ConstantRange X = getSignedRange(UMax->getOperand(0));
for (unsigned i = 1, e = UMax->getNumOperands(); i != e; ++i)
X = X.umax(getSignedRange(UMax->getOperand(i)));
- return ConservativeResult.intersectWith(X);
+ return setSignedRange(UMax, ConservativeResult.intersectWith(X));
}
if (const SCEVUDivExpr *UDiv = dyn_cast<SCEVUDivExpr>(S)) {
ConstantRange X = getSignedRange(UDiv->getLHS());
ConstantRange Y = getSignedRange(UDiv->getRHS());
- return ConservativeResult.intersectWith(X.udiv(Y));
+ return setSignedRange(UDiv, ConservativeResult.intersectWith(X.udiv(Y)));
}
if (const SCEVZeroExtendExpr *ZExt = dyn_cast<SCEVZeroExtendExpr>(S)) {
ConstantRange X = getSignedRange(ZExt->getOperand());
- return ConservativeResult.intersectWith(X.zeroExtend(BitWidth));
+ return setSignedRange(ZExt,
+ ConservativeResult.intersectWith(X.zeroExtend(BitWidth)));
}
if (const SCEVSignExtendExpr *SExt = dyn_cast<SCEVSignExtendExpr>(S)) {
ConstantRange X = getSignedRange(SExt->getOperand());
- return ConservativeResult.intersectWith(X.signExtend(BitWidth));
+ return setSignedRange(SExt,
+ ConservativeResult.intersectWith(X.signExtend(BitWidth)));
}
if (const SCEVTruncateExpr *Trunc = dyn_cast<SCEVTruncateExpr>(S)) {
ConstantRange X = getSignedRange(Trunc->getOperand());
- return ConservativeResult.intersectWith(X.truncate(BitWidth));
+ return setSignedRange(Trunc,
+ ConservativeResult.intersectWith(X.truncate(BitWidth)));
}
if (const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(S)) {
ConstantRange ExtEndRange = EndRange.sextOrTrunc(BitWidth*2+1);
if (ExtStartRange.add(ExtMaxBECountRange.multiply(ExtStepRange)) !=
ExtEndRange)
- return ConservativeResult;
+ return setSignedRange(AddRec, ConservativeResult);
APInt Min = APIntOps::smin(StartRange.getSignedMin(),
EndRange.getSignedMin());
APInt Max = APIntOps::smax(StartRange.getSignedMax(),
EndRange.getSignedMax());
if (Min.isMinSignedValue() && Max.isMaxSignedValue())
- return ConservativeResult;
- return ConservativeResult.intersectWith(ConstantRange(Min, Max+1));
+ return setSignedRange(AddRec, ConservativeResult);
+ return setSignedRange(AddRec,
+ ConservativeResult.intersectWith(ConstantRange(Min, Max+1)));
}
}
- return ConservativeResult;
+ return setSignedRange(AddRec, ConservativeResult);
}
if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
// For a SCEVUnknown, ask ValueTracking.
if (!U->getValue()->getType()->isIntegerTy() && !TD)
- return ConservativeResult;
+ return setSignedRange(U, ConservativeResult);
unsigned NS = ComputeNumSignBits(U->getValue(), TD);
if (NS == 1)
- return ConservativeResult;
- return ConservativeResult.intersectWith(
+ return setSignedRange(U, ConservativeResult);
+ return setSignedRange(U, ConservativeResult.intersectWith(
ConstantRange(APInt::getSignedMinValue(BitWidth).ashr(NS - 1),
- APInt::getSignedMaxValue(BitWidth).ashr(NS - 1)+1));
+ APInt::getSignedMaxValue(BitWidth).ashr(NS - 1)+1)));
}
- return ConservativeResult;
+ return setSignedRange(S, ConservativeResult);
}
/// createSCEV - We know that there is no SCEV for the specified value.
// LLVM IR canonical form means we need only traverse the left operands.
SmallVector<const SCEV *, 4> AddOps;
AddOps.push_back(getSCEV(U->getOperand(1)));
- for (Value *Op = U->getOperand(0);
- Op->getValueID() == Instruction::Add + Value::InstructionVal;
- Op = U->getOperand(0)) {
+ for (Value *Op = U->getOperand(0); ; Op = U->getOperand(0)) {
+ unsigned Opcode = Op->getValueID() - Value::InstructionVal;
+ if (Opcode != Instruction::Add && Opcode != Instruction::Sub)
+ break;
U = cast<Operator>(Op);
- AddOps.push_back(getSCEV(U->getOperand(1)));
+ const SCEV *Op1 = getSCEV(U->getOperand(1));
+ if (Opcode == Instruction::Sub)
+ AddOps.push_back(getNegativeSCEV(Op1));
+ else
+ AddOps.push_back(Op1);
}
AddOps.push_back(getSCEV(U->getOperand(0)));
return getAddExpr(AddOps);
if (Pair.second) {
BackedgeTakenInfo BECount = ComputeBackedgeTakenCount(L);
if (BECount.Exact != getCouldNotCompute()) {
- assert(BECount.Exact->isLoopInvariant(L) &&
- BECount.Max->isLoopInvariant(L) &&
+ assert(isLoopInvariant(BECount.Exact, L) &&
+ isLoopInvariant(BECount.Max, L) &&
"Computed backedge-taken count isn't loop invariant for loop!");
++NumTripCountsComputed;
ValueExprMapType::iterator It =
ValueExprMap.find(static_cast<Value *>(I));
if (It != ValueExprMap.end()) {
+ const SCEV *Old = It->second;
+
// SCEVUnknown for a PHI either means that it has an unrecognized
// structure, or it's a PHI that's in the progress of being computed
// by createNodeForPHI. In the former case, additional loop trip
// count information isn't going to change anything. In the later
// case, createNodeForPHI will perform the necessary updates on its
// own when it gets to that point.
- if (!isa<PHINode>(I) || !isa<SCEVUnknown>(It->second)) {
- ValuesAtScopes.erase(It->second);
+ if (!isa<PHINode>(I) || !isa<SCEVUnknown>(Old)) {
+ ValuesAtScopes.erase(Old);
+ UnsignedRanges.erase(Old);
+ SignedRanges.erase(Old);
ValueExprMap.erase(It);
}
if (PHINode *PN = dyn_cast<PHINode>(I))
ValueExprMapType::iterator It = ValueExprMap.find(static_cast<Value *>(I));
if (It != ValueExprMap.end()) {
- ValuesAtScopes.erase(It->second);
+ const SCEV *Old = It->second;
+ ValuesAtScopes.erase(Old);
+ UnsignedRanges.erase(Old);
+ SignedRanges.erase(Old);
ValueExprMap.erase(It);
if (PHINode *PN = dyn_cast<PHINode>(I))
ConstantEvolutionLoopExitValue.erase(PN);
PushDefUseChildren(I, Worklist);
}
+
+ // Forget all contained loops too, to avoid dangling entries in the
+ // ValuesAtScopes map.
+ for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
+ forgetLoop(*I);
}
/// forgetValue - This method should be called by the client when it has
ValueExprMapType::iterator It = ValueExprMap.find(static_cast<Value *>(I));
if (It != ValueExprMap.end()) {
- ValuesAtScopes.erase(It->second);
+ const SCEV *Old = It->second;
+ ValuesAtScopes.erase(Old);
+ UnsignedRanges.erase(Old);
+ SignedRanges.erase(Old);
ValueExprMap.erase(It);
if (PHINode *PN = dyn_cast<PHINode>(I))
ConstantEvolutionLoopExitValue.erase(PN);
// At this point, we would like to compute how many iterations of the
// loop the predicate will return true for these inputs.
- if (LHS->isLoopInvariant(L) && !RHS->isLoopInvariant(L)) {
+ if (isLoopInvariant(LHS, L) && !isLoopInvariant(RHS, L)) {
// If there is a loop-invariant, force it into the RHS.
std::swap(LHS, RHS);
Cond = ICmpInst::getSwappedPredicate(Cond);
// We can only recognize very limited forms of loop index expressions, in
// particular, only affine AddRec's like {C1,+,C2}.
const SCEVAddRecExpr *IdxExpr = dyn_cast<SCEVAddRecExpr>(Idx);
- if (!IdxExpr || !IdxExpr->isAffine() || IdxExpr->isLoopInvariant(L) ||
+ if (!IdxExpr || !IdxExpr->isAffine() || isLoopInvariant(IdxExpr, L) ||
!isa<SCEVConstant>(IdxExpr->getOperand(0)) ||
!isa<SCEVConstant>(IdxExpr->getOperand(1)))
return getCouldNotCompute();
// as both operands could be addrecs loop-invariant in each other's loop.
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(RHS)) {
const Loop *L = AR->getLoop();
- if (LHS->isLoopInvariant(L) && LHS->properlyDominates(L->getHeader(), DT)) {
+ if (isLoopInvariant(LHS, L) && LHS->properlyDominates(L->getHeader(), DT)) {
std::swap(LHS, RHS);
Pred = ICmpInst::getSwappedPredicate(Pred);
Changed = true;
ScalarEvolution::HowManyLessThans(const SCEV *LHS, const SCEV *RHS,
const Loop *L, bool isSigned) {
// Only handle: "ADDREC < LoopInvariant".
- if (!RHS->isLoopInvariant(L)) return getCouldNotCompute();
+ if (!isLoopInvariant(RHS, L)) return getCouldNotCompute();
const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(LHS);
if (!AddRec || AddRec->getLoop() != L)
ScalarEvolution::ScalarEvolution()
: FunctionPass(ID), FirstUnknown(0) {
+ initializeScalarEvolutionPass(*PassRegistry::getPassRegistry());
}
bool ScalarEvolution::runOnFunction(Function &F) {
BackedgeTakenCounts.clear();
ConstantEvolutionLoopExitValue.clear();
ValuesAtScopes.clear();
+ UnsignedRanges.clear();
+ SignedRanges.clear();
UniqueSCEVs.clear();
SCEVAllocator.Reset();
}
if (L) {
OS << "\t\t" "Exits: ";
const SCEV *ExitValue = SE.getSCEVAtScope(SV, L->getParentLoop());
- if (!ExitValue->isLoopInvariant(L)) {
+ if (!SE.isLoopInvariant(ExitValue, L)) {
OS << "<<Unknown>>";
} else {
OS << *ExitValue;
PrintLoopInfo(OS, &SE, *I);
}
+bool ScalarEvolution::isLoopInvariant(const SCEV *S, const Loop *L) {
+ switch (S->getSCEVType()) {
+ case scConstant:
+ return true;
+ case scTruncate:
+ case scZeroExtend:
+ case scSignExtend:
+ return isLoopInvariant(cast<SCEVCastExpr>(S)->getOperand(), L);
+ case scAddRecExpr: {
+ const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(S);
+
+ // Add recurrences are never invariant in the function-body (null loop).
+ if (!L)
+ return false;
+
+ // This recurrence is variant w.r.t. L if L contains AR's loop.
+ if (L->contains(AR->getLoop()))
+ return false;
+
+ // This recurrence is invariant w.r.t. L if AR's loop contains L.
+ if (AR->getLoop()->contains(L))
+ return true;
+
+ // This recurrence is variant w.r.t. L if any of its operands
+ // are variant.
+ for (SCEVAddRecExpr::op_iterator I = AR->op_begin(), E = AR->op_end();
+ I != E; ++I)
+ if (!isLoopInvariant(*I, L))
+ return false;
+
+ // Otherwise it's loop-invariant.
+ return true;
+ }
+ case scAddExpr:
+ case scMulExpr:
+ case scUMaxExpr:
+ case scSMaxExpr: {
+ const SCEVNAryExpr *NAry = cast<SCEVNAryExpr>(S);
+ for (SCEVNAryExpr::op_iterator I = NAry->op_begin(), E = NAry->op_end();
+ I != E; ++I)
+ if (!isLoopInvariant(*I, L))
+ return false;
+ return true;
+ }
+ case scUDivExpr: {
+ const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(S);
+ return isLoopInvariant(UDiv->getLHS(), L) &&
+ isLoopInvariant(UDiv->getRHS(), L);
+ }
+ case scUnknown:
+ // All non-instruction values are loop invariant. All instructions are loop
+ // invariant if they are not contained in the specified loop.
+ // Instructions are never considered invariant in the function body
+ // (null loop) because they are defined within the "loop".
+ if (Instruction *I = dyn_cast<Instruction>(cast<SCEVUnknown>(S)->getValue()))
+ return L && !L->contains(I);
+ return true;
+ case scCouldNotCompute:
+ llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
+ return false;
+ default: break;
+ }
+ llvm_unreachable("Unknown SCEV kind!");
+ return false;
+}
+
+bool ScalarEvolution::hasComputableLoopEvolution(const SCEV *S, const Loop *L) {
+ switch (S->getSCEVType()) {
+ case scConstant:
+ return false;
+ case scTruncate:
+ case scZeroExtend:
+ case scSignExtend:
+ return hasComputableLoopEvolution(cast<SCEVCastExpr>(S)->getOperand(), L);
+ case scAddRecExpr:
+ return cast<SCEVAddRecExpr>(S)->getLoop() == L;
+ case scAddExpr:
+ case scMulExpr:
+ case scUMaxExpr:
+ case scSMaxExpr: {
+ const SCEVNAryExpr *NAry = cast<SCEVNAryExpr>(S);
+ bool HasVarying = false;
+ for (SCEVNAryExpr::op_iterator I = NAry->op_begin(), E = NAry->op_end();
+ I != E; ++I) {
+ const SCEV *Op = *I;
+ if (!isLoopInvariant(Op, L)) {
+ if (hasComputableLoopEvolution(Op, L))
+ HasVarying = true;
+ else
+ return false;
+ }
+ }
+ return HasVarying;
+ }
+ case scUDivExpr: {
+ const SCEVUDivExpr *UDiv = cast<SCEVUDivExpr>(S);
+ bool HasVarying = false;
+ if (!isLoopInvariant(UDiv->getLHS(), L)) {
+ if (hasComputableLoopEvolution(UDiv->getLHS(), L))
+ HasVarying = true;
+ else
+ return false;
+ }
+ if (!isLoopInvariant(UDiv->getRHS(), L)) {
+ if (hasComputableLoopEvolution(UDiv->getRHS(), L))
+ HasVarying = true;
+ else
+ return false;
+ }
+ return HasVarying;
+ }
+ case scUnknown:
+ return false;
+ case scCouldNotCompute:
+ llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
+ return false;
+ default: break;
+ }
+ llvm_unreachable("Unknown SCEV kind!");
+ return false;
+}
projects / oota-llvm.git / blobdiff