[semantic-arc-opts] Teach semantic-arc-opts how to handle structs with multiple non-trivial values.

include/swift/SIL/OwnershipUtils.h

@@ -498,6 +498,10 @@ struct OwnedValueIntroducerKind {
     /// branch predecessors.
     Phi,
 
+    /// An owned value that is from a struct that has multiple operands that are
+    /// owned.
+    Struct,
+
     /// An owned value that is a function argument.
     FunctionArgument,
 
@@ -522,6 +526,8 @@ struct OwnedValueIntroducerKind {
       return OwnedValueIntroducerKind(Apply);
     case ValueKind::BeginApplyResult:
       return OwnedValueIntroducerKind(BeginApply);
+    case ValueKind::StructInst:
+      return OwnedValueIntroducerKind(Struct);
     case ValueKind::SILPhiArgument: {
       auto *phiArg = cast<SILPhiArgument>(value);
       if (dyn_cast_or_null<TryApplyInst>(phiArg->getSingleTerminator())) {
@@ -614,6 +620,7 @@ struct OwnedValueIntroducer {
     case OwnedValueIntroducerKind::TryApply:
     case OwnedValueIntroducerKind::LoadTake:
     case OwnedValueIntroducerKind::Phi:
+    case OwnedValueIntroducerKind::Struct:
     case OwnedValueIntroducerKind::FunctionArgument:
     case OwnedValueIntroducerKind::PartialApplyInit:
     case OwnedValueIntroducerKind::AllocBoxInit:
@@ -631,6 +638,7 @@ struct OwnedValueIntroducer {
     switch (kind) {
     case OwnedValueIntroducerKind::Phi:
       return true;
+    case OwnedValueIntroducerKind::Struct:
     case OwnedValueIntroducerKind::Copy:
     case OwnedValueIntroducerKind::LoadCopy:
     case OwnedValueIntroducerKind::Apply:

lib/SIL/Utils/OwnershipUtils.cpp

@@ -485,6 +485,9 @@ void OwnedValueIntroducerKind::print(llvm::raw_ostream &os) const {
   case OwnedValueIntroducerKind::Phi:
     os << "Phi";
     return;
+  case OwnedValueIntroducerKind::Struct:
+    os << "Struct";
+    return;
   case OwnedValueIntroducerKind::FunctionArgument:
     os << "FunctionArgument";
     return;

lib/SILOptimizer/Transforms/SemanticARCOpts.cpp

@@ -54,6 +54,7 @@ class OwnershipPhiOperand {
 public:
   enum Kind {
     Branch,
+    Struct,
   };
 
 private:
@@ -65,6 +66,7 @@ class OwnershipPhiOperand {
   static Optional<OwnershipPhiOperand> get(const Operand *op) {
     switch (op->getUser()->getKind()) {
     case SILInstructionKind::BranchInst:
+    case SILInstructionKind::StructInst:
       return {{const_cast<Operand *>(op)}};
     default:
       return None;
@@ -75,6 +77,8 @@ class OwnershipPhiOperand {
     switch (op->getUser()->getKind()) {
     case SILInstructionKind::BranchInst:
       return Kind::Branch;
+    case SILInstructionKind::StructInst:
+      return Kind::Struct;
     default:
       llvm_unreachable("unhandled case?!");
     }
@@ -100,6 +104,8 @@ class OwnershipPhiOperand {
     switch (getKind()) {
     case Kind::Branch:
       return true;
+    case Kind::Struct:
+      return false;
     }
   }
 
@@ -113,6 +119,8 @@ class OwnershipPhiOperand {
 
   bool visitResults(function_ref<bool(SILValue)> visitor) const {
     switch (getKind()) {
+    case Kind::Struct:
+      return visitor(cast<StructInst>(getInst()));
     case Kind::Branch: {
       auto *br = cast<BranchInst>(getInst());
       unsigned opNum = getOperandNumber();
@@ -576,6 +584,11 @@ static SILValue convertIntroducerToGuaranteed(OwnedValueIntroducer introducer) {
     phiArg->setOwnershipKind(ValueOwnershipKind::Guaranteed);
     return phiArg;
   }
+  case OwnedValueIntroducerKind::Struct: {
+    auto *si = cast<StructInst>(introducer.value);
+    si->setOwnershipKind(ValueOwnershipKind::Guaranteed);
+    return si;
+  }
   case OwnedValueIntroducerKind::Copy:
   case OwnedValueIntroducerKind::LoadCopy:
   case OwnedValueIntroducerKind::Apply:
@@ -1084,6 +1097,20 @@ static bool getIncomingJoinedLiveRangeOperands(
     });
   }
 
+  if (auto *svi = dyn_cast<SingleValueInstruction>(joinedLiveRange)) {
+    return llvm::all_of(svi->getAllOperands(), [&](const Operand &op) {
+      // skip type dependent operands.
+      if (op.isTypeDependent())
+        return true;
+
+      auto phiOp = OwnershipPhiOperand::get(&op);
+      if (!phiOp)
+        return false;
+      resultingOperands.push_back(*phiOp);
+      return true;
+    });
+  }
+
   llvm_unreachable("Unhandled joined live range?!");
 }
 

test/SILOptimizer/semantic-arc-opts.sil

@@ -2548,3 +2548,16 @@ bb1:
 bb2(%39 : @owned $Klass):
   unreachable
 }
+
+// CHECK-LABEL: sil [ossa] @struct_with_multiple_nontrivial_operands : $@convention(thin) (@guaranteed Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
+// CHECK-NOT: copy_value
+// CHECK: } // end sil function 'struct_with_multiple_nontrivial_operands'
+sil [ossa] @struct_with_multiple_nontrivial_operands : $@convention(thin) (@guaranteed Builtin.NativeObject, @guaranteed Builtin.NativeObject) -> () {
+bb0(%0 : @guaranteed $Builtin.NativeObject, %1 : @guaranteed $Builtin.NativeObject):
+  %0a = copy_value %0 : $Builtin.NativeObject
+  %1a = copy_value %1 : $Builtin.NativeObject
+  %2 = struct $NativeObjectPair(%0a : $Builtin.NativeObject, %1a : $Builtin.NativeObject)
+  destroy_value %2 : $NativeObjectPair
+  %9999 = tuple()
+  return %9999 : $()
+}