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Reapply "Revert "[devirtualization] Re-enable devirtualization of pure inherited protocol conformances with a new refactored implementation and a better test.""
Now that the external vs linkonce_odr witness table issue has been sorted out. Swift SVN r17424
This commit is contained in:
Michael Gottesman
@@ -428,6 +428,116 @@ static ApplyInst *replaceDynApplyWithStaticApply(ApplyInst *AI, SILFunction *F,
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return SAI;
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}
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namespace {
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struct DevirtInfo {
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SILValue Self = SILValue();
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ArrayRef<Substitution> Subs = ArrayRef<Substitution>();
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SILType SubstCalleeType = SILType();
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SILType Type = SILType();
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DevirtInfo() {}
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DevirtInfo(SILValue Self, SILType SubstCalleeType)
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: Self(Self), SubstCalleeType(SubstCalleeType) {}
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};
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}
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static bool optimizeApplyOfNormalConformanceWitnessMethod(
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ApplyInst *AI, WitnessMethodInst *WMI, ProtocolConformance *C,
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SILFunction *F, DevirtInfo Info={}) {
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// Ok, we found the member we are looking for. Devirtualize away!
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SILBuilder Builder(AI);
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SILLocation Loc = AI->getLoc();
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FunctionRefInst *FRI = Builder.createFunctionRef(Loc, F);
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// Collect args from the apply inst.
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ArrayRef<Operand> ApplyArgs = AI->getArgumentOperands();
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SmallVector<SILValue, 4> Args;
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// Add self to the Args list...
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if (!Info.Self)
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Info.Self = ApplyArgs[0].get();
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Args.push_back(Info.Self);
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// Then add the rest of the arguments.
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for (auto &A : ApplyArgs.slice(1))
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Args.push_back(A.get());
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SmallVector<Substitution, 16> NewSubstList(Info.Subs.begin(),
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Info.Subs.end());
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// Add the non-self-derived substitutions from the original application.
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assert(AI->getSubstitutions().size() && "Subst list must not be empty");
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assert(AI->getSubstitutions()[0].Archetype->getSelfProtocol() &&
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"The first substitution needS to be a 'self' substitution.");
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for (auto &origSub : AI->getSubstitutions().slice(1)) {
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if (!origSub.Archetype->isSelfDerived())
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NewSubstList.push_back(origSub);
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}
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if (!Info.SubstCalleeType)
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Info.SubstCalleeType = AI->getSubstCalleeSILType();
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if (!Info.Type)
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Info.Type = AI->getType();
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ApplyInst *SAI = Builder.createApply(Loc, FRI, Info.SubstCalleeType,
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Info.Type, NewSubstList, Args);
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AI->replaceAllUsesWith(SAI);
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AI->eraseFromParent();
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NumAMI++;
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return true;
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}
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static bool optimizeApplyOfInheritedConformanceWitnessMethod(
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ApplyInst *AI, WitnessMethodInst *WMI, ProtocolConformance *C,
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SILFunction *F, SILWitnessTable *WT) {
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// Since we do not need to worry about substitutions, we can just insert an
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// upcast of self to the appropriate type.
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SILValue Self = AI->getArgumentOperands()[0].get();
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CanType Ty = WT->getConformance()->getType()->getCanonicalType();
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SILType SILTy = SILType::getPrimitiveType(Ty, Self.getType().getCategory());
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SILType SelfTy = Self.getType();
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(void)SelfTy;
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assert(SILTy.isSuperclassOf(SelfTy) &&
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"Should only create upcasts for sub class devirtualization.");
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Self = SILBuilder(AI).createUpcast(AI->getLoc(), Self, SILTy);
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SmallVector<Substitution, 16> SelfDerivedSubstitutions;
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for (auto &origSub : AI->getSubstitutions())
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if (origSub.Archetype->isSelfDerived())
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SelfDerivedSubstitutions.push_back(origSub);
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// If we have more than 1 substitution on AI that is self derived, that means
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// we either have a property or a typealias. We currently do not specialize
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// those correctly implying that we will have an archetype instead of a
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// concrete type here that we can not work with. Thus bail and don't do
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// anything.
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if (SelfDerivedSubstitutions.size() > 1)
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return false;
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// Grab self and substitute into the old generic callee type to get the new
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// non-generic callee type.
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assert(SelfDerivedSubstitutions.size() == 1 &&
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"Must have a substitution for self.");
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Substitution S = AI->getSubstitutions()[0];
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S.Replacement = Ty;
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CanSILFunctionType OrigType = AI->getOrigCalleeType();
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CanSILFunctionType SubstCalleeType = OrigType->substInterfaceGenericArgs(
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AI->getModule(), AI->getModule().getSwiftModule(),
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ArrayRef<Substitution>(S));
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SILType SubstCalleeSILType = SILType::getPrimitiveObjectType(SubstCalleeType);
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// Then pass of our new self to the normal protocol conformance witness method
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// handling code.
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DevirtInfo DInfo = DevirtInfo{Self, SubstCalleeSILType};
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return optimizeApplyOfNormalConformanceWitnessMethod(AI, WMI, C, F, DInfo);
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}
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/// Devirtualize apply instructions that call witness_method instructions:
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///
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/// %8 = witness_method $Optional<UInt16>, #LogicValue.getLogicValue!1
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@@ -444,77 +554,36 @@ bool SILDevirtualizer::optimizeApplyOfWitnessMethod(ApplyInst *AI,
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// Lookup the function reference in the witness tables.
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SILFunction *F;
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ArrayRef<Substitution> Subs;
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SILWitnessTable *WitnessTable;
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std::tie(F, WitnessTable, Subs) =
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SILWitnessTable *WT;
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std::tie(F, WT, Subs) =
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AI->getModule().findFuncInWitnessTable(C, AMI->getMember());
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if (!F) {
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assert(!WitnessTable && "WitnessTable should always be null if F is.");
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assert(!WT && "WitnessTable should always be null if F is.");
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DEBUG(llvm::dbgs() << " FAIL: Did not find a matching witness "
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"table or witness method.\n");
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return false;
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}
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assert(WitnessTable && "WitnessTable should never be null if F is not.");
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assert(WT && "WitnessTable should never be null if F is not.");
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// Ok, we found the member we are looking for. Devirtualize away!
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SILBuilder Builder(AI);
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SILLocation Loc = AI->getLoc();
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FunctionRefInst *FRI = Builder.createFunctionRef(Loc, F);
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// Start by looking at the type of the witness table and the type of the
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// witness table. If they are different, we have some combination of generic
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// conformance, specialized generic conformance or inherited conformance. If
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// we just have a simple conformance handle it quickly and effortlessly.
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auto WTCType = WT->getConformance()->getType()->getCanonicalType();
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auto CType = C->getType()->getCanonicalType();
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if (WTCType == CType)
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return optimizeApplyOfNormalConformanceWitnessMethod(AI, AMI, C, F);
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// Collect args from the apply inst.
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ArrayRef<Operand> ApplyArgs = AI->getArgumentOperands();
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SmallVector<SILValue, 4> Args;
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// Ok, we do not have a simple specialization to do here. First find out if
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// there is a specialized conformance in our type hierarchy. If there is no
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// such thing, we have a pure inherited protocol conformance.
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if (Subs.empty())
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return optimizeApplyOfInheritedConformanceWitnessMethod(AI, AMI, C, F, WT);
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// Begin by upcasting self to the appropriate type if we have an inherited
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// conformance...
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SILValue Self = ApplyArgs[0].get();
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if (C->getKind() == ProtocolConformanceKind::Inherited) {
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CanType Ty = WitnessTable->getConformance()->getType()->getCanonicalType();
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SILType SILTy = SILType::getPrimitiveType(Ty, Self.getType().getCategory());
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SILType SelfTy = Self.getType();
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(void)SelfTy;
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if (Subs.size()) {
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// If we have substitutions then we are an inherited specialized
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// conformance. Substitute in the generic type so we upcast correctly.
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GenericParamList *GP = C->getSubstitutedGenericParams();
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if (!GP)
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return false;
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TypeSubstitutionMap TSM = GP->getSubstitutionMap(Subs);
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SILTy = SILTy.subst(F->getModule(), F->getModule().getSwiftModule(), TSM);
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SelfTy =
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SelfTy.subst(F->getModule(), F->getModule().getSwiftModule(), TSM);
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}
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assert(SILTy.isSuperclassOf(SelfTy) &&
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"Should only create upcasts for sub class devirtualization.");
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Self = Builder.createUpcast(Loc, Self, SILTy);
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}
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// and then adding in either the original or newly upcasted value.
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Args.push_back(Self);
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// Then add the rest of the arguments.
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for (auto &A : ApplyArgs.slice(1))
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Args.push_back(A.get());
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SmallVector<Substitution, 16> NewSubstList(Subs.begin(), Subs.end());
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// Add the non-self-derived substitutions from the original application.
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assert(AI->getSubstitutions().size() && "Subst list must not be empty");
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assert(AI->getSubstitutions()[0].Archetype->getSelfProtocol() &&
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"The first substitution needS to be a 'self' substitution.");
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for (auto &origSub : AI->getSubstitutions().slice(1)) {
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if (!origSub.Archetype->isSelfDerived())
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NewSubstList.push_back(origSub);
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}
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ApplyInst *SAI = Builder.createApply(Loc, FRI, AI->getSubstCalleeSILType(),
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AI->getType(), NewSubstList, Args);
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AI->replaceAllUsesWith(SAI);
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AI->eraseFromParent();
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NumAMI++;
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return true;
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// Otherwise we have a mixed specialized, or mixed specialized inherited
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// protocol conformance to deal with. Bail.
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return false;
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}
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/// Devirtualize protocol_method + project_existential + init_existential
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