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[Constraint system] Hoist some common code in matchTypes. #11905

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merged 1 commit into from
Sep 13, 2017
Merged

[Constraint system] Hoist some common code in matchTypes. #11905

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38 changes: 13 additions & 25 deletions lib/Sema/CSSimplify.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1608,18 +1608,25 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,

// If either (or both) types are type variables, unify the type variables.
if (typeVar1 || typeVar2) {
// Handle the easy case of both being type variables, and being
// identical, first.
if (typeVar1 && typeVar2) {
auto rep1 = getRepresentative(typeVar1);
auto rep2 = getRepresentative(typeVar2);
if (rep1 == rep2) {
// We already merged these two types, so this constraint is
// trivially solved.
return SolutionKind::Solved;
}
}

switch (kind) {
case ConstraintKind::Bind:
case ConstraintKind::BindToPointerType:
case ConstraintKind::Equal: {
if (typeVar1 && typeVar2) {
auto rep1 = getRepresentative(typeVar1);
auto rep2 = getRepresentative(typeVar2);
if (rep1 == rep2) {
// We already merged these two types, so this constraint is
// trivially solved.
return SolutionKind::Solved;
}

// If exactly one of the type variables can bind to an lvalue, we
// can't merge these two type variables.
Expand Down Expand Up @@ -1675,28 +1682,13 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
assignFixedType(typeVar1, type2);
}
return SolutionKind::Solved;
} else if (typeVar1 && typeVar2) {
auto rep1 = getRepresentative(typeVar1);
auto rep2 = getRepresentative(typeVar2);
if (rep1 == rep2) {
return SolutionKind::Solved;
}
}

return formUnsolvedResult();
}

case ConstraintKind::ArgumentTupleConversion:
case ConstraintKind::Conversion:
if (typeVar1 && typeVar2) {
auto rep1 = getRepresentative(typeVar1);
auto rep2 = getRepresentative(typeVar2);
if (rep1 == rep2) {
// We already merged these two types, so this constraint is
// trivially solved.
return SolutionKind::Solved;
}
}
LLVM_FALLTHROUGH;

case ConstraintKind::Subtype:
Expand Down Expand Up @@ -1739,12 +1731,8 @@ ConstraintSystem::matchTypes(Type type1, Type type2, ConstraintKind kind,
case ConstraintKind::OperatorArgumentConversion:
// We couldn't solve this constraint. If only one of the types is a type
// variable, perhaps we can do something with it below.
if (typeVar1 && typeVar2) {
if (typeVar1 == typeVar2) return SolutionKind::Solved;

if (typeVar1 && typeVar2)
return formUnsolvedResult();
}

break;

case ConstraintKind::ApplicableFunction:
Expand Down