[Wasm GC] Fix getSentType() of BrOn with an unreachable input (#3993)

Without this fix, DCE would end up calling getHeapType() on the unreachable
input, which hits an assertion as it has no heap type.

2 files changed, 21 insertions, 0 deletions

diff --git a/test/passes/dce_all-features.txt b/test/passes/dce_all-features.txt
index bc1e24951..779405c13 100644
--- a/test/passes/dce_all-features.txt
+++ b/test/passes/dce_all-features.txt
@@ -591,3 +591,9 @@
   )
  )
 )
+(module
+ (type $none_=>_ref|any| (func (result (ref any))))
+ (func $foo (result (ref any))
+  (unreachable)
+ )
+)
diff --git a/test/passes/dce_all-features.wast b/test/passes/dce_all-features.wast
index 0f0416f66..95344be93 100644
--- a/test/passes/dce_all-features.wast
+++ b/test/passes/dce_all-features.wast
@@ -792,3 +792,18 @@
     )
   )
 )
+(module
+  (func $foo (result (ref any))
+    (block $label$1 (result (ref any))
+      ;; this break has an unreachable input, and so it does not have a heap type
+      ;; there, and no heap type to send on the branch. this tests we do not hit
+      ;; the assertion in getHeapType() if we call that.
+      (br_on_non_null $label$1
+        (block (result anyref)
+          (unreachable)
+        )
+      )
+      (unreachable)
+    )
+  )
+)