Merge pull request #71881 from meg-gupta/fixmem2reg

Fix mem2reg of lexical enum stack locations

Author: meg-gupta

include/swift/SIL/SILBuilder.h

@@ -1707,9 +1707,11 @@ class SILBuilder {
 
   EnumInst *createEnum(SILLocation Loc, SILValue Operand,
                        EnumElementDecl *Element, SILType Ty) {
-    return createEnum(Loc, Operand, Element, Ty,
-                      Operand ? Operand->getOwnershipKind()
-                              : ValueOwnershipKind(OwnershipKind::None));
+    return createEnum(
+        Loc, Operand, Element, Ty,
+        Operand ? getSILValueOwnership({Operand}, Ty)
+                : (Ty.isMoveOnly() ? ValueOwnershipKind(OwnershipKind::Owned)
+                                   : ValueOwnershipKind(OwnershipKind::None)));
   }
 
   EnumInst *createEnum(SILLocation Loc, SILValue Operand,

include/swift/SIL/ValueUtils.h

@@ -18,7 +18,9 @@
 namespace swift {
 
 /// Attempt to merge the ValueOwnershipKind of the passed in range's
-/// SILValues. Returns Optional<None> if we found an incompatibility.
+/// SILValues. Returns OwnershipKind::Any if we found an incompatibility.
+/// If \p is a move-only type, we return OwnershipKind::Owned since such
+/// values can have deinit side-effects.
 ///
 /// NOTE: This assumes that the passed in SILValues are not values used as type
 /// dependent operands.

lib/SIL/Utils/ValueUtils.cpp

@@ -26,8 +26,7 @@ ValueOwnershipKind swift::getSILValueOwnership(ArrayRef<SILValue> values,
 
   auto mergedOwnership = ValueOwnershipKind::merge(range);
 
-  // If we have a move only type, and the merged ownership is none, we return
-  // Owned ownership kind.
+  // If we have a move only type, return owned ownership.
   if (ty && ty.isMoveOnly() && mergedOwnership == OwnershipKind::None) {
     return OwnershipKind::Owned;
   }