CodeMotion: check the ownership of arguments when sinking arguments

So far we only checked the ownership of incoming values.
But even if the incoming instruction has no ownership, the argument may have.
This can happen with enums which are constructed with a non-payload case:

   %1 = enum $Optional<C>, #Optional.none!enumelt
   br bb3(%1)
 bb1(%3 : @owned $Optional<C>):

Fixes an ownership verification error:
rdar://142506300

Author: eeckstein

lib/SILOptimizer/Transforms/SILCodeMotion.cpp

@@ -1184,6 +1184,16 @@ static bool sinkArgument(EnumCaseDataflowContext &Context, SILBasicBlock *BB, un
   if (hasOwnershipOperandsOrResults(FSI))
     return false;
 
+  // Even if the incoming instruction has no ownership, the argument may have.
+  // This can happen with enums which are constructed with a non-payload case:
+  //
+  //   %1 = enum $Optional<C>, #Optional.none!enumelt
+  //   br bb3(%1)
+  // bb1(%3 : @owned $Optional<C>):
+  //
+  if (BB->getArgument(ArgNum)->getOwnershipKind() != OwnershipKind::None)
+    return false;
+
   // The list of identical instructions.
   SmallVector<SingleValueInstruction *, 8> Clones;
   Clones.push_back(FSI);

test/SILOptimizer/earlycodemotion.sil

@@ -552,6 +552,28 @@ bb3(%12 : $Bool):
   return %12 : $Bool
 }
 
+// CHECK-LABEL: sil [ossa] @dont_sink_owned_trivial_enum :
+// CHECK:       bb1:
+// CHECK-NEXT:    enum
+// CHECK:       bb2:
+// CHECK-NEXT:    enum
+// CHECK:       bb3([[A:%.*]] : @owned $Optional<C>):
+// CHECK-NEXT:    return [[A]]
+// CHECK:       } // end sil function 'dont_sink_owned_trivial_enum'
+sil [ossa] @dont_sink_owned_trivial_enum : $@convention(thin) () -> @owned Optional<C> {
+bb0:
+  cond_br undef, bb1, bb2
+bb1:
+  %2 = enum $Optional<C>, #Optional.none!enumelt
+  br bb3(%2)
+bb2:
+  %4 = enum $Optional<C>, #Optional.none!enumelt
+  br bb3(%4)
+bb3(%6 : @owned $Optional<C>):
+  return %6
+}
+
+
 // Sink retain down the successors so we can pair up retain with release on the
 // fast path.
 class Test {