Add a unit test for get_access_base with mark_uninitialized.

Author: atrick

test/SILOptimizer/accessbase_unit.sil

@@ -65,3 +65,24 @@ sil @test_access_global : $@convention(thin) () -> () {
   %retval = tuple ()
   return %retval : $()
 }
+
+// CHECK-LABEL: begin running test {{.*}} on test_mark_uninitialized_inst: get_access_base
+// CHECK: Address:  %{{.*}} = mark_uninitialized [var] [[ALLOC:%.*]] : $*C
+// CHECK: Base:     [[ALLOC]] = alloc_stack [var_decl] $C
+// CHECK-LABEL: end running test {{.*}} on test_mark_uninitialized_inst: get_access_base
+// CHECK-LABEL: begin running test {{.*}} on test_mark_uninitialized_inst: swift_get_access_base
+// CHECK: Address:  %{{.*}} = mark_uninitialized [var] [[ALLOC:%.*]] : $*C
+// CHECK: Base: stack - [[ALLOC]] = alloc_stack [var_decl] $C
+// CHECK-LABEL: end running test {{.*}} on test_mark_uninitialized_inst: swift_get_access_base
+sil [ossa] @test_mark_uninitialized_inst : $@convention(thin) (@owned C) -> () {
+bb0(%0 : @owned $C):
+  %1 = alloc_stack [var_decl] $C, let
+  %2 = mark_uninitialized [var] %1 : $*C
+  specify_test "get_access_base %2"
+  specify_test "swift_get_access_base %2"
+  assign %0 to %2 : $*C
+  destroy_addr %2 : $*C
+  dealloc_stack %1 : $*C
+  %9999 = tuple()
+  return %9999 : $()
+}