Fix ownershipKind of the phi's that the SILSSAUpdater creates for RLE

When the available values have none ownership on one side and owned on the other,
we need to merge their ownershipKind for their phi argument

Author: meg-gupta

lib/SILOptimizer/Transforms/RedundantLoadElimination.cpp

@@ -1328,12 +1328,20 @@ SILValue RLEContext::computePredecessorLocationValue(SILBasicBlock *BB,
     Values.push_back({CurBB, LSValue::reduce(L, &BB->getModule(), LSValues, IPt)});
   }
 
+  auto ownershipRange =
+      makeTransformRange(llvm::make_range(Values.begin(), Values.end()),
+                         [](std::pair<SILBasicBlock *, SILValue> v) {
+                           return v.second.getOwnershipKind();
+                         });
+
+  auto mergedOwnershipKind = ValueOwnershipKind::merge(ownershipRange);
+
   // Finally, collect all the values for the SILArgument, materialize it using
   // the SSAUpdater.
   Updater.initialize(
       L.getType(&BB->getModule(), TypeExpansionContext(*BB->getParent()))
           .getObjectType(),
-      Values[0].second.getOwnershipKind());
+      mergedOwnershipKind);
 
   SmallVector<SILPhiArgument *, 8> insertedPhis;
   Updater.setInsertedPhis(&insertedPhis);

test/SILOptimizer/redundant_load_elim_ossa_complex.sil

@@ -23,6 +23,10 @@ struct TripleKlass {
   var val3 : Klass
 }
 
+public enum FakeOptional<T> {
+  case none
+  case some(T)
+}
 sil [ossa] @use_klass : $@convention(thin) (@owned Klass) -> ()
 sil [ossa] @use_nontrivialstruct : $@convention(thin) (@owned NonTrivialStruct) -> ()
 
@@ -818,3 +822,28 @@ bb9:
   return %val1 : $Klass
 }
 
+// CHECK-LABEL: @rle_ownershipkindmergetest :
+// CHECK-NOT: load
+// CHECK-LABEL: end sil function 'rle_ownershipkindmergetest'
+sil [ossa] @rle_ownershipkindmergetest : $@convention(thin) (@owned FakeOptional<Klass>) -> () {
+bb0(%0 : @owned $FakeOptional<Klass>):
+  %3 = alloc_stack $FakeOptional<Klass>
+  store %0 to [init] %3 : $*FakeOptional<Klass>
+  cond_br undef, bb1, bb2
+
+bb1:
+  %4 = enum $FakeOptional<Klass>, #FakeOptional.none!enumelt
+  store %4 to [assign] %3 : $*FakeOptional<Klass>
+  br bb3
+
+bb2:
+  br bb3
+
+bb3:
+  %49 = load [copy] %3 : $*FakeOptional<Klass>
+  destroy_value %49 : $FakeOptional<Klass>
+  destroy_addr %3 : $*FakeOptional<Klass>
+  dealloc_stack %3 : $*FakeOptional<Klass>
+  %res = tuple ()
+  return %res : $()
+}