MoveOnlyDeinitInsertion: don't call the deinit if the destroy is preceeded by a drop_deinit

rdar://105798769

Author: eeckstein

lib/SILOptimizer/Mandatory/MoveOnlyDeinitInsertion.cpp

@@ -62,7 +62,8 @@ static bool performTransform(SILFunction &fn) {
 
       if (auto *dvi = dyn_cast<DestroyValueInst>(inst)) {
         auto destroyType = dvi->getOperand()->getType();
-        if (destroyType.isMoveOnlyNominalType()) {
+        if (destroyType.isMoveOnlyNominalType() &&
+            !isa<DropDeinitInst>(lookThroughOwnershipInsts(dvi->getOperand()))) {
           LLVM_DEBUG(llvm::dbgs() << "Handling: " << *dvi);
           auto *nom = destroyType.getNominalOrBoundGenericNominal();
           assert(nom);
@@ -88,7 +89,8 @@ static bool performTransform(SILFunction &fn) {
 
       if (auto *dai = dyn_cast<DestroyAddrInst>(inst)) {
         auto destroyType = dai->getOperand()->getType();
-        if (destroyType.isLoadable(fn) && destroyType.isMoveOnlyNominalType()) {
+        if (destroyType.isLoadable(fn) && destroyType.isMoveOnlyNominalType() &&
+            !isa<DropDeinitInst>(dai->getOperand())) {
           LLVM_DEBUG(llvm::dbgs() << "Handling: " << *dai);
           auto *nom = destroyType.getNominalOrBoundGenericNominal();
           assert(nom);

test/SILOptimizer/moveonly_deinit_insertion.sil

@@ -309,6 +309,48 @@ bb6:
   return %14 : $()
 }
 
+//===----------------------------------------------------------------------===//
+//                              drop_deinit Tests
+//===----------------------------------------------------------------------===//
+
+// CHECK-LABEL: sil [ossa] @dropDeinitOnStruct : $@convention(thin) (@owned TrivialStruct) -> () {
+// CHECK:         %1 = drop_deinit %0
+// CHECK-NEXT:    destroy_value %1
+// CHECK:       } // end sil function 'dropDeinitOnStruct'
+sil [ossa] @dropDeinitOnStruct : $@convention(thin) (@owned TrivialStruct) -> () {
+bb0(%0 : @owned $TrivialStruct):
+  %1 = drop_deinit %0 : $TrivialStruct
+  destroy_value %1 : $TrivialStruct
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @dropDeinitOnMovedStruct : $@convention(thin) (@owned TrivialStruct) -> () {
+// CHECK:         %1 = drop_deinit %0
+// CHECK-NEXT:    %2 = move_value %1
+// CHECK-NEXT:    destroy_value %2
+// CHECK:       } // end sil function 'dropDeinitOnMovedStruct'
+sil [ossa] @dropDeinitOnMovedStruct : $@convention(thin) (@owned TrivialStruct) -> () {
+bb0(%0 : @owned $TrivialStruct):
+  %1 = drop_deinit %0 : $TrivialStruct
+  %2 = move_value %1 : $TrivialStruct
+  destroy_value %2 : $TrivialStruct
+  %9999 = tuple()
+  return %9999 : $()
+}
+
+// CHECK-LABEL: sil [ossa] @dropDeinitOnIndirectStruct : $@convention(thin) (@in TrivialStruct) -> () {
+// CHECK:         %1 = drop_deinit %0
+// CHECK-NEXT:    destroy_addr %1
+// CHECK:       } // end sil function 'dropDeinitOnIndirectStruct'
+sil [ossa] @dropDeinitOnIndirectStruct : $@convention(thin) (@in TrivialStruct) -> () {
+bb0(%0 : $*TrivialStruct):
+  %1 = drop_deinit %0 : $*TrivialStruct
+  destroy_addr %1 : $*TrivialStruct
+  %9999 = tuple()
+  return %9999 : $()
+}
+
 sil @$s4main5KlassCfD : $@convention(method) (@owned Klass) -> ()
 sil @$s4main5KlassCACycfc : $@convention(method) (@owned Klass) -> @owned Klass
 sil @$s4main5KlassCfd : $@convention(method) (@guaranteed Klass) -> @owned Builtin.NativeObject