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[ConstraintSystem] Instead of favoring existing operator bindings,

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order them first in the main disjunction partition.
This commit is contained in:
Holly Borla
2020-10-29 14:39:11 -07:00
parent 8dd2008f7e
commit c9100c46e7
1 changed files with 24 additions and 41 deletions
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65
lib/Sema/CSSolver.cpp
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@@ -2015,7 +2015,9 @@ static Constraint *tryOptimizeGenericDisjunction(
// Performance hack: favor operator overloads with decl or type we're already
// binding elsewhere in this expression.
static void existingOperatorBindingsForDisjunction(ConstraintSystem &CS, ArrayRef<Constraint *> constraints, SmallVectorImpl<Constraint *> &found) {
static void existingOperatorBindingsForDisjunction(ConstraintSystem &CS,
ArrayRef<Constraint *> constraints,
SmallVectorImpl<unsigned> &found) {
auto *choice = constraints.front();
if (choice->getKind() != ConstraintKind::BindOverload)
return;
@@ -2026,47 +2028,28 @@ static void existingOperatorBindingsForDisjunction(ConstraintSystem &CS, ArrayRe
auto decl = overload.getDecl();
if (!decl->isOperator())
return;
auto baseName = decl->getBaseName();
SmallSet<TypeBase *, 8> typesFound;
SmallSet<CanType, 8> typesFound;
for (auto overload : CS.getResolvedOverloads()) {
auto resolved = overload.second;
if (!resolved.choice.isDecl())
continue;
auto representativeDecl = resolved.choice.getDecl();
auto representativeDecl = resolved.choice.getDecl();
if (!representativeDecl->isOperator())
continue;
if (representativeDecl->getBaseName() == baseName) {
// Favor exactly the same decl, if we have a binding to the same name.
for (auto *constraint : constraints) {
if (constraint->isFavored())
continue;
auto choice = constraint->getOverloadChoice();
if (choice.getDecl() == representativeDecl) {
found.push_back(constraint);
break;
}
}
} else {
// Favor the same type, if we have a binding to an operator of that type.
auto representativeType = representativeDecl->getInterfaceType();
if (typesFound.count(representativeType.getPointer()))
continue;
typesFound.insert(representativeType.getPointer());
typesFound.insert(representativeDecl->getInterfaceType()->getCanonicalType());
}
for (auto *constraint : constraints) {
if (constraint->isFavored())
continue;
auto choice = constraint->getOverloadChoice();
if (choice.getDecl()->getInterfaceType()->isEqual(representativeType)) {
found.push_back(constraint);
break;
}
}
}
for (auto index : indices(constraints)) {
auto *constraint = constraints[index];
if (constraint->isFavored())
continue;
auto *decl = constraint->getOverloadChoice().getDecl();
if (typesFound.count(decl->getInterfaceType()->getCanonicalType()))
found.push_back(index);
}
}
@@ -2074,11 +2057,6 @@ void ConstraintSystem::partitionDisjunction(
ArrayRef<Constraint *> Choices, SmallVectorImpl<unsigned> &Ordering,
SmallVectorImpl<unsigned> &PartitionBeginning) {
SmallVector<Constraint *, 4> existing;
existingOperatorBindingsForDisjunction(*this, Choices, existing);
for (auto constraint : existing)
favorConstraint(constraint);
// Apply a special-case rule for favoring one generic function over
// another.
if (auto favored = tryOptimizeGenericDisjunction(DC, Choices)) {
@@ -2105,12 +2083,18 @@ void ConstraintSystem::partitionDisjunction(
// First collect some things that we'll generally put near the beginning or
// end of the partitioning.
SmallVector<unsigned, 4> favored;
SmallVector<unsigned, 4> everythingElse;
SmallVector<unsigned, 4> simdOperators;
SmallVector<unsigned, 4> disabled;
SmallVector<unsigned, 4> unavailable;
// Add existing operator bindings to the main partition first. This often
// helps the solver find a solution fast.
existingOperatorBindingsForDisjunction(*this, Choices, everythingElse);
for (auto index : everythingElse)
taken.insert(Choices[index]);
// First collect disabled and favored constraints.
forEachChoice(Choices, [&](unsigned index, Constraint *constraint) -> bool {
if (constraint->isDisabled()) {
@@ -2170,7 +2154,6 @@ void ConstraintSystem::partitionDisjunction(
}
};
SmallVector<unsigned, 4> everythingElse;
// Gather the remaining options.
forEachChoice(Choices, [&](unsigned index, Constraint *constraint) -> bool {
everythingElse.push_back(index);
@@ -2206,8 +2189,8 @@ Constraint *ConstraintSystem::selectDisjunction() {
if (firstFavored == secondFavored) {
// Look for additional choices to favor
SmallVector<Constraint *, 4> firstExisting;
SmallVector<Constraint *, 4> secondExisting;
SmallVector<unsigned, 4> firstExisting;
SmallVector<unsigned, 4> secondExisting;
existingOperatorBindingsForDisjunction(*cs, first->getNestedConstraints(), firstExisting);
firstFavored = firstExisting.size() ? firstExisting.size() : first->countActiveNestedConstraints();