SILCombine: don't fold unchecked_take_enum_data_addr - destroy_addr of enums with deinit

Destroying whole non-copyable enums with a deinit would wrongly trigger calling its deinit.

Author: eeckstein

lib/SILOptimizer/SILCombiner/SILCombinerMiscVisitors.cpp

@@ -1146,6 +1146,10 @@ SILInstruction *SILCombiner::visitUncheckedTakeEnumDataAddrInst(
   }
 
   if (onlyDestroys) {
+    // Destroying whole non-copyable enums with a deinit would wrongly trigger calling its deinit.
+    if (tedai->getOperand()->getType().isValueTypeWithDeinit())
+      return nullptr;
+
     // The unchecked_take_enum_data_addr is dead: remove it and replace all
     // destroys with a destroy of its operand.
     while (!tedai->use_empty()) {

test/SILOptimizer/sil_combine_moveonly.sil

@@ -185,3 +185,29 @@ bb0(%0 : @owned $S2):
   return %r
 }
 
+// CHECK-LABEL: sil [ossa] @dont_fold_destroy_of_take_enum_with_deinit_ossa :
+// CHECK:       bb0(%0 : $*MaybeFileDescriptor):
+// CHECK-NEXT:    %1 = unchecked_take_enum_data_addr %0
+// CHECK-NEXT:    destroy_addr %1
+// CHECK:       } // end sil function 'dont_fold_destroy_of_take_enum_with_deinit_ossa'
+sil [ossa] @dont_fold_destroy_of_take_enum_with_deinit_ossa : $@convention(thin) (@in MaybeFileDescriptor) -> () {
+bb0(%0 : $*MaybeFileDescriptor):
+  %1 = unchecked_take_enum_data_addr %0, #MaybeFileDescriptor.some!enumelt
+  destroy_addr %1
+  %r = tuple ()
+  return %r : $()
+}
+
+// CHECK-LABEL: sil @dont_fold_destroy_of_take_enum_with_deinit :
+// CHECK:       bb0(%0 : $*MaybeFileDescriptor):
+// CHECK-NEXT:    %1 = unchecked_take_enum_data_addr %0
+// CHECK-NEXT:    destroy_addr %1
+// CHECK:       } // end sil function 'dont_fold_destroy_of_take_enum_with_deinit'
+sil @dont_fold_destroy_of_take_enum_with_deinit : $@convention(thin) (@in MaybeFileDescriptor) -> () {
+bb0(%0 : $*MaybeFileDescriptor):
+  %1 = unchecked_take_enum_data_addr %0, #MaybeFileDescriptor.some!enumelt
+  destroy_addr %1
+  %r = tuple ()
+  return %r : $()
+}
+