getHeapTypeCounts() must note select types for references (#5540)

Without this we hit an assertion on trying to write the binary, on a missing
heap type.

3 files changed, 31 insertions, 2 deletions

diff --git a/src/ir/module-utils.cpp b/src/ir/module-utils.cpp
index a6d2633ff..a2abcd5b5 100644
--- a/src/ir/module-utils.cpp
+++ b/src/ir/module-utils.cpp
@@ -63,6 +63,9 @@ struct CodeScanner
       counts.note(call->target->type);
     } else if (curr->is<RefNull>()) {
       counts.note(curr->type);
+    } else if (curr->is<Select>() && curr->type.isRef()) {
+      // This select will be annotated in the binary, so note it.
+      counts.note(curr->type);
     } else if (curr->is<StructNew>()) {
       counts.note(curr->type);
     } else if (curr->is<ArrayNew>()) {
diff --git a/test/lit/passes/gufa-vs-cfp.wast b/test/lit/passes/gufa-vs-cfp.wast
index 0a678af4f..a2fb8f5df 100644
--- a/test/lit/passes/gufa-vs-cfp.wast
+++ b/test/lit/passes/gufa-vs-cfp.wast
@@ -679,12 +679,12 @@
 ;; Subtyping: Create both a subtype and a supertype, with identical constants
 ;;            for the shared field, and get the supertype.
 (module
+  ;; CHECK:      (type $struct (struct (field i32)))
+  (type $struct (struct i32))
   ;; CHECK:      (type $none_=>_i32 (func (result i32)))
 
   ;; CHECK:      (type $none_=>_none (func))
 
-  ;; CHECK:      (type $struct (struct (field i32)))
-  (type $struct (struct i32))
   ;; CHECK:      (type $substruct (struct_subtype (field i32) (field f64) $struct))
   (type $substruct (struct_subtype i32 f64 $struct))
 
diff --git a/test/lit/select-gc.wat b/test/lit/select-gc.wat
new file mode 100644
index 000000000..8cc1d4ca7
--- /dev/null
+++ b/test/lit/select-gc.wat
@@ -0,0 +1,26 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py and should not be edited.
+
+;; RUN: wasm-opt -all --roundtrip %s -S -o - | filecheck %s
+
+;; Check that annotated select is propery roundtripped, even if the type is
+;; only used in that one place in the whole module.
+
+(module
+  ;; CHECK:      (type $struct (struct ))
+  (type $struct (struct))
+
+  ;; CHECK:      (func $foo (type $none_=>_anyref) (result anyref)
+  ;; CHECK-NEXT:  (select (result (ref null $struct))
+  ;; CHECK-NEXT:   (ref.null none)
+  ;; CHECK-NEXT:   (ref.null none)
+  ;; CHECK-NEXT:   (i32.const 1)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $foo (result anyref)
+    (select (result (ref null $struct))
+      (ref.null any)
+      (ref.null eq)
+      (i32.const 1)
+    )
+  )
+)