From 5611a528b2a3bcd37aedd863c6058f99095c9a35 Mon Sep 17 00:00:00 2001
From: Alon Zakai <azakai@google.com>
Date: Mon, 30 Dec 2024 13:14:59 -0800
Subject: [wasm-reduce] Reduce struct.new arguments away when possible (#7118)

If all the fields of a struct.new are defaultable, see if replacing it with a
struct.new_default preserves the behavior, and reduce that way if so.

Also add a missing --closed-world to the --remove-unused-types
invocation. Without that, it was erroring and not working, which I
noticed when testing this. The test also checks that.
---
 test/reduce/gc.wast | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 test/reduce/gc.wast

(limited to 'test/reduce/gc.wast')

diff --git a/test/reduce/gc.wast b/test/reduce/gc.wast
new file mode 100644
index 000000000..98d1cd075
--- /dev/null
+++ b/test/reduce/gc.wast
@@ -0,0 +1,28 @@
+(module
+  (rec
+    (type $A (struct (field (mut i32)) (field funcref)))
+    ;; This type can be optimized away.
+    (type $unused (struct))
+  )
+
+  (global $A (ref null $A) (struct.new $A
+    ;; These particular values are not used, and can be removed, leaving the
+    ;; struct.new as struct.new_default.
+    (i32.const 0)
+    (ref.func $use-global)
+  ))
+
+  (func $use-global (export "use-global") (result i32)
+    ;; This function stores 42 in the global struct, then reads and returns
+    ;; that. We don't manage to optimize away anything in this function, which
+    ;; only serves to keep alive the type and the global for the above testing.
+    (struct.set $A 0
+      (global.get $A)
+      (i32.const 42)
+    )
+    (struct.get $A 0
+      (global.get $A)
+    )
+  )
+)
+
-- 
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