[Wasm GC] Refinalize in Vacuum (#5412)

We use TypeUpdater there, which handles updating unreachability. But with wasm GC
we also need to refinalize if we refine types. Somehow, this was not noticed until now,
but the new ref.cast null assertion on not losing type info was enough to uncover
this long-existing issue.

1 files changed, 18 insertions, 0 deletions

diff --git a/test/lit/passes/vacuum-gc.wast b/test/lit/passes/vacuum-gc.wast
index f84988f46..c7ff5a37f 100644
--- a/test/lit/passes/vacuum-gc.wast
+++ b/test/lit/passes/vacuum-gc.wast
@@ -2,6 +2,7 @@
 ;; RUN: wasm-opt %s --vacuum -all -S -o - | filecheck %s
 
 (module
+  ;; CHECK:      (type ${} (struct ))
   (type ${} (struct))
 
   ;; CHECK:      (func $drop-ref-as (type $anyref_=>_none) (param $x anyref)
@@ -92,4 +93,21 @@
       )
     )
   )
+
+  ;; CHECK:      (func $ref.cast.null.block (type $ref|${}|_=>_dataref) (param $ref (ref ${})) (result dataref)
+  ;; CHECK-NEXT:  (ref.cast ${}
+  ;; CHECK-NEXT:   (local.get $ref)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $ref.cast.null.block (param $ref (ref ${})) (result (ref null data))
+    ;; We can vacuum away the block, which will make this ref.cast null operate
+    ;; on a non-nullable input. That is, we are refining the input to the cast.
+    ;; The cast must be updated properly following that, to be a non-nullable
+    ;; cast.
+    (ref.cast null ${}
+      (block (result (ref null ${}))
+        (local.get $ref)
+      )
+    )
+  )
 )