Revert r312765 for now, since it causes assertions when building

lang/spidermonkey24.

Reported by:	antoine
PR:		215649
This commit is contained in:
Dimitry Andric 2017-01-26 20:18:28 +00:00
parent a136ca542c
commit b9389c99a5
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=312831
4 changed files with 36 additions and 103 deletions

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@ -495,29 +495,10 @@ namespace llvm {
/// The typedef for ExprValueMap.
///
typedef std::pair<Value *, ConstantInt *> ValueOffsetPair;
typedef DenseMap<const SCEV *, SetVector<ValueOffsetPair>> ExprValueMapType;
typedef DenseMap<const SCEV *, SetVector<Value *>> ExprValueMapType;
/// ExprValueMap -- This map records the original values from which
/// the SCEV expr is generated from.
///
/// We want to represent the mapping as SCEV -> ValueOffsetPair instead
/// of SCEV -> Value:
/// Suppose we know S1 expands to V1, and
/// S1 = S2 + C_a
/// S3 = S2 + C_b
/// where C_a and C_b are different SCEVConstants. Then we'd like to
/// expand S3 as V1 - C_a + C_b instead of expanding S2 literally.
/// It is helpful when S2 is a complex SCEV expr.
///
/// In order to do that, we represent ExprValueMap as a mapping from
/// SCEV to ValueOffsetPair. We will save both S1->{V1, 0} and
/// S2->{V1, C_a} into the map when we create SCEV for V1. When S3
/// is expanded, it will first expand S2 to V1 - C_a because of
/// S2->{V1, C_a} in the map, then expand S3 to V1 - C_a + C_b.
///
/// Note: S->{V, Offset} in the ExprValueMap means S can be expanded
/// to V - Offset.
ExprValueMapType ExprValueMap;
/// The typedef for ValueExprMap.
@ -1200,7 +1181,7 @@ namespace llvm {
bool containsAddRecurrence(const SCEV *S);
/// Return the Value set from which the SCEV expr is generated.
SetVector<ValueOffsetPair> *getSCEVValues(const SCEV *S);
SetVector<Value *> *getSCEVValues(const SCEV *S);
/// Erase Value from ValueExprMap and ExprValueMap.
void eraseValueFromMap(Value *V);

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@ -325,8 +325,7 @@ namespace llvm {
PointerType *PTy, Type *Ty, Value *V);
/// \brief Find a previous Value in ExprValueMap for expand.
ScalarEvolution::ValueOffsetPair
FindValueInExprValueMap(const SCEV *S, const Instruction *InsertPt);
Value *FindValueInExprValueMap(const SCEV *S, const Instruction *InsertPt);
Value *expand(const SCEV *S);

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@ -3378,28 +3378,8 @@ bool ScalarEvolution::containsAddRecurrence(const SCEV *S) {
return F.FoundOne;
}
/// Try to split a SCEVAddExpr into a pair of {SCEV, ConstantInt}.
/// If \p S is a SCEVAddExpr and is composed of a sub SCEV S' and an
/// offset I, then return {S', I}, else return {\p S, nullptr}.
static std::pair<const SCEV *, ConstantInt *> splitAddExpr(const SCEV *S) {
const auto *Add = dyn_cast<SCEVAddExpr>(S);
if (!Add)
return {S, nullptr};
if (Add->getNumOperands() != 2)
return {S, nullptr};
auto *ConstOp = dyn_cast<SCEVConstant>(Add->getOperand(0));
if (!ConstOp)
return {S, nullptr};
return {Add->getOperand(1), ConstOp->getValue()};
}
/// Return the ValueOffsetPair set for \p S. \p S can be represented
/// by the value and offset from any ValueOffsetPair in the set.
SetVector<ScalarEvolution::ValueOffsetPair> *
ScalarEvolution::getSCEVValues(const SCEV *S) {
/// Return the Value set from S.
SetVector<Value *> *ScalarEvolution::getSCEVValues(const SCEV *S) {
ExprValueMapType::iterator SI = ExprValueMap.find_as(S);
if (SI == ExprValueMap.end())
return nullptr;
@ -3407,31 +3387,24 @@ ScalarEvolution::getSCEVValues(const SCEV *S) {
if (VerifySCEVMap) {
// Check there is no dangling Value in the set returned.
for (const auto &VE : SI->second)
assert(ValueExprMap.count(VE.first));
assert(ValueExprMap.count(VE));
}
#endif
return &SI->second;
}
/// Erase Value from ValueExprMap and ExprValueMap. ValueExprMap.erase(V)
/// cannot be used separately. eraseValueFromMap should be used to remove
/// V from ValueExprMap and ExprValueMap at the same time.
/// Erase Value from ValueExprMap and ExprValueMap. If ValueExprMap.erase(V) is
/// not used together with forgetMemoizedResults(S), eraseValueFromMap should be
/// used instead to ensure whenever V->S is removed from ValueExprMap, V is also
/// removed from the set of ExprValueMap[S].
void ScalarEvolution::eraseValueFromMap(Value *V) {
ValueExprMapType::iterator I = ValueExprMap.find_as(V);
if (I != ValueExprMap.end()) {
const SCEV *S = I->second;
// Remove {V, 0} from the set of ExprValueMap[S]
if (SetVector<ValueOffsetPair> *SV = getSCEVValues(S))
SV->remove({V, nullptr});
// Remove {V, Offset} from the set of ExprValueMap[Stripped]
const SCEV *Stripped;
ConstantInt *Offset;
std::tie(Stripped, Offset) = splitAddExpr(S);
if (Offset != nullptr) {
if (SetVector<ValueOffsetPair> *SV = getSCEVValues(Stripped))
SV->remove({V, Offset});
}
SetVector<Value *> *SV = getSCEVValues(S);
// Remove V from the set of ExprValueMap[S]
if (SV)
SV->remove(V);
ValueExprMap.erase(V);
}
}
@ -3446,26 +3419,11 @@ const SCEV *ScalarEvolution::getSCEV(Value *V) {
S = createSCEV(V);
// During PHI resolution, it is possible to create two SCEVs for the same
// V, so it is needed to double check whether V->S is inserted into
// ValueExprMap before insert S->{V, 0} into ExprValueMap.
// ValueExprMap before insert S->V into ExprValueMap.
std::pair<ValueExprMapType::iterator, bool> Pair =
ValueExprMap.insert({SCEVCallbackVH(V, this), S});
if (Pair.second) {
ExprValueMap[S].insert({V, nullptr});
// If S == Stripped + Offset, add Stripped -> {V, Offset} into
// ExprValueMap.
const SCEV *Stripped = S;
ConstantInt *Offset = nullptr;
std::tie(Stripped, Offset) = splitAddExpr(S);
// If stripped is SCEVUnknown, don't bother to save
// Stripped -> {V, offset}. It doesn't simplify and sometimes even
// increase the complexity of the expansion code.
// If V is GetElementPtrInst, don't save Stripped -> {V, offset}
// because it may generate add/sub instead of GEP in SCEV expansion.
if (Offset != nullptr && !isa<SCEVUnknown>(Stripped) &&
!isa<GetElementPtrInst>(V))
ExprValueMap[Stripped].insert({V, Offset});
}
if (Pair.second)
ExprValueMap[S].insert(V);
}
return S;
}
@ -3478,8 +3436,8 @@ const SCEV *ScalarEvolution::getExistingSCEV(Value *V) {
const SCEV *S = I->second;
if (checkValidity(S))
return S;
eraseValueFromMap(V);
forgetMemoizedResults(S);
ValueExprMap.erase(I);
}
return nullptr;
}
@ -3717,8 +3675,8 @@ void ScalarEvolution::forgetSymbolicName(Instruction *PN, const SCEV *SymName) {
if (!isa<PHINode>(I) ||
!isa<SCEVUnknown>(Old) ||
(I != PN && Old == SymName)) {
eraseValueFromMap(It->first);
forgetMemoizedResults(Old);
ValueExprMap.erase(It);
}
}
@ -4097,7 +4055,7 @@ const SCEV *ScalarEvolution::createAddRecFromPHI(PHINode *PN) {
// to create an AddRecExpr for this PHI node. We can not keep this temporary
// as it will prevent later (possibly simpler) SCEV expressions to be added
// to the ValueExprMap.
eraseValueFromMap(PN);
ValueExprMap.erase(PN);
}
return nullptr;
@ -5477,8 +5435,8 @@ ScalarEvolution::getBackedgeTakenInfo(const Loop *L) {
// case, createNodeForPHI will perform the necessary updates on its
// own when it gets to that point.
if (!isa<PHINode>(I) || !isa<SCEVUnknown>(Old)) {
eraseValueFromMap(It->first);
forgetMemoizedResults(Old);
ValueExprMap.erase(It);
}
if (PHINode *PN = dyn_cast<PHINode>(I))
ConstantEvolutionLoopExitValue.erase(PN);
@ -5523,8 +5481,8 @@ void ScalarEvolution::forgetLoop(const Loop *L) {
ValueExprMapType::iterator It =
ValueExprMap.find_as(static_cast<Value *>(I));
if (It != ValueExprMap.end()) {
eraseValueFromMap(It->first);
forgetMemoizedResults(It->second);
ValueExprMap.erase(It);
if (PHINode *PN = dyn_cast<PHINode>(I))
ConstantEvolutionLoopExitValue.erase(PN);
}
@ -5557,8 +5515,8 @@ void ScalarEvolution::forgetValue(Value *V) {
ValueExprMapType::iterator It =
ValueExprMap.find_as(static_cast<Value *>(I));
if (It != ValueExprMap.end()) {
eraseValueFromMap(It->first);
forgetMemoizedResults(It->second);
ValueExprMap.erase(It);
if (PHINode *PN = dyn_cast<PHINode>(I))
ConstantEvolutionLoopExitValue.erase(PN);
}

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@ -1625,10 +1625,9 @@ Value *SCEVExpander::expandCodeFor(const SCEV *SH, Type *Ty) {
return V;
}
ScalarEvolution::ValueOffsetPair
SCEVExpander::FindValueInExprValueMap(const SCEV *S,
const Instruction *InsertPt) {
SetVector<ScalarEvolution::ValueOffsetPair> *Set = SE.getSCEVValues(S);
Value *SCEVExpander::FindValueInExprValueMap(const SCEV *S,
const Instruction *InsertPt) {
SetVector<Value *> *Set = SE.getSCEVValues(S);
// If the expansion is not in CanonicalMode, and the SCEV contains any
// sub scAddRecExpr type SCEV, it is required to expand the SCEV literally.
if (CanonicalMode || !SE.containsAddRecurrence(S)) {
@ -1637,21 +1636,21 @@ SCEVExpander::FindValueInExprValueMap(const SCEV *S,
// Choose a Value from the set which dominates the insertPt.
// insertPt should be inside the Value's parent loop so as not to break
// the LCSSA form.
for (auto const &VOPair : *Set) {
Value *V = VOPair.first;
ConstantInt *Offset = VOPair.second;
for (auto const &Ent : *Set) {
Instruction *EntInst = nullptr;
if (V && isa<Instruction>(V) && (EntInst = cast<Instruction>(V)) &&
S->getType() == V->getType() &&
if (Ent && isa<Instruction>(Ent) &&
(EntInst = cast<Instruction>(Ent)) &&
S->getType() == Ent->getType() &&
EntInst->getFunction() == InsertPt->getFunction() &&
SE.DT.dominates(EntInst, InsertPt) &&
(SE.LI.getLoopFor(EntInst->getParent()) == nullptr ||
SE.LI.getLoopFor(EntInst->getParent())->contains(InsertPt)))
return {V, Offset};
SE.LI.getLoopFor(EntInst->getParent())->contains(InsertPt))) {
return Ent;
}
}
}
}
return {nullptr, nullptr};
return nullptr;
}
// The expansion of SCEV will either reuse a previous Value in ExprValueMap,
@ -1699,14 +1698,10 @@ Value *SCEVExpander::expand(const SCEV *S) {
Builder.SetInsertPoint(InsertPt);
// Expand the expression into instructions.
ScalarEvolution::ValueOffsetPair VO = FindValueInExprValueMap(S, InsertPt);
Value *V = VO.first;
Value *V = FindValueInExprValueMap(S, InsertPt);
if (!V)
V = visit(S);
else if (VO.second) {
V = Builder.CreateSub(V, VO.second);
}
// Remember the expanded value for this SCEV at this location.
//
@ -1919,7 +1914,7 @@ Value *SCEVExpander::findExistingExpansion(const SCEV *S,
// Use expand's logic which is used for reusing a previous Value in
// ExprValueMap.
if (Value *Val = FindValueInExprValueMap(S, At).first)
if (Value *Val = FindValueInExprValueMap(S, At))
return Val;
// There is potential to make this significantly smarter, but this simple