diff --git a/src/ir/possible-contents.cpp b/src/ir/possible-contents.cpp
index 9170a16524d..c018cf628d7 100644
--- a/src/ir/possible-contents.cpp
+++ b/src/ir/possible-contents.cpp
@@ -2454,6 +2454,11 @@ Flower::Flower(Module& wasm, const PassOptions& options)
     }
   }
 
+  // configureAll functions are called from outside the module, as if exported.
+  for (auto func : Intrinsics(wasm).getConfigureAllFunctions()) {
+    calledFromOutside.insert(func);
+  }
+
   // Apply changes to all functions called from outside.
   for (auto funcName : calledFromOutside) {
     auto* func = wasm.getFunction(funcName);
diff --git a/test/lit/passes/gufa-configureAll.wast b/test/lit/passes/gufa-configureAll.wast
new file mode 100644
index 00000000000..274ad8fa1d4
--- /dev/null
+++ b/test/lit/passes/gufa-configureAll.wast
@@ -0,0 +1,103 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+
+;; RUN: foreach %s %t wasm-opt --gufa --closed-world -all -S -o - | filecheck %s
+
+;; Test that configureAll is respected: referred functions are assumed to be
+;; called from outside the module, depsite closed world.
+
+(module
+  ;; CHECK:      (type $externs (array (mut externref)))
+  (type $externs (array (mut externref)))
+
+  ;; CHECK:      (type $funcs (array (mut funcref)))
+  (type $funcs (array (mut funcref)))
+
+  ;; CHECK:      (type $bytes (array (mut i8)))
+  (type $bytes (array (mut i8)))
+
+  ;; CHECK:      (type $3 (func (param i32) (result i32)))
+
+  ;; CHECK:      (type $configureAll (func (param (ref null $externs) (ref null $funcs) (ref null $bytes) externref)))
+  (type $configureAll (func (param (ref null $externs)) (param (ref null $funcs)) (param (ref null $bytes)) (param externref)))
+
+  ;; CHECK:      (type $5 (func))
+
+  ;; CHECK:      (import "wasm:js-prototypes" "configureAll" (func $configureAll (type $configureAll) (param (ref null $externs) (ref null $funcs) (ref null $bytes) externref)))
+  (import "wasm:js-prototypes" "configureAll" (func $configureAll (type $configureAll)))
+
+  ;; CHECK:      (data $bytes "12345678")
+  (data $bytes "12345678")
+
+  ;; CHECK:      (elem $externs externref (item (ref.null noextern)))
+  (elem $externs externref
+    (ref.null extern)
+  )
+
+  ;; CHECK:      (elem $funcs func $configured)
+  (elem $funcs funcref
+    (ref.func $configured)
+  )
+
+  ;; CHECK:      (elem $other func $unconfigured)
+  (elem $other funcref
+    (ref.func $unconfigured)
+  )
+
+  ;; CHECK:      (start $start)
+  (start $start)
+
+  ;; CHECK:      (func $start (type $5)
+  ;; CHECK-NEXT:  (call $configureAll
+  ;; CHECK-NEXT:   (array.new_elem $externs $externs
+  ;; CHECK-NEXT:    (i32.const 0)
+  ;; CHECK-NEXT:    (i32.const 1)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:   (array.new_elem $funcs $funcs
+  ;; CHECK-NEXT:    (i32.const 0)
+  ;; CHECK-NEXT:    (i32.const 1)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:   (array.new_data $bytes $bytes
+  ;; CHECK-NEXT:    (i32.const 0)
+  ;; CHECK-NEXT:    (i32.const 8)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:   (ref.null noextern)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $start
+    (call $configureAll
+      (array.new_elem $externs $externs
+        (i32.const 0) (i32.const 1))
+      (array.new_elem $funcs $funcs
+        (i32.const 0) (i32.const 1))
+      (array.new_data $bytes $bytes
+        (i32.const 0) (i32.const 8))
+      (ref.null extern)
+    )
+  )
+
+  ;; CHECK:      (func $configured (type $3) (param $x i32) (result i32)
+  ;; CHECK-NEXT:  (i32.eqz
+  ;; CHECK-NEXT:   (local.get $x)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $configured (param $x i32) (result i32)
+    ;; The call from outside the module, through configureAll, is the only call
+    ;; we have - without it, this would be unreachable code, and optimized away.
+    (i32.eqz
+      (local.get $x)
+    )
+  )
+
+  ;; CHECK:      (func $unconfigured (type $3) (param $x i32) (result i32)
+  ;; CHECK-NEXT:  (i32.eqz
+  ;; CHECK-NEXT:   (unreachable)
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $unconfigured (param $x i32) (result i32)
+    ;; As above, but *not* in configureAll (though it is in a table, so it is
+    ;; not entirely removed) - so we do optimize.
+    (i32.eqz
+      (local.get $x)
+    )
+  )
+)