.

Author: tekknolagi

zjit/src/cruby_methods.rs

@@ -640,9 +640,9 @@ fn inline_basic_object_neq(fun: &mut hir::Function, block: hir::BlockId, recv: h
             let result = fun.push_insn(block, hir::Insn::Const { val: hir::Const::Value(Qfalse) });
             return Some(result);
         }
-        if fun.is_a(other, types::StringExact) && fun.assume_expected_cfunc(block, recv_class, ID!(eq), rb_str_equal as _, state) {
+        if fun.is_a(other, types::String) && fun.assume_expected_cfunc(block, recv_class, ID!(eq), rb_str_equal as _, state) {
             let recv = fun.coerce_to(block, recv, types::StringExact, state);
-            let other = fun.coerce_to(block, other, types::StringExact, state);
+            let other = fun.coerce_to(block, other, types::String, state);
             let return_type = types::BoolExact;
             let elidable = true;
             // TODO(max): Make StringEqual its own opcode so that we can later constant-fold StringEqual(a, a) => true

zjit/src/hir/opt_tests.rs

@@ -553,6 +553,41 @@ mod hir_opt_tests {
         ");
     }
 
+    #[test]
+    fn test_optimize_string_neq_string_subclass() {
+        eval(r#"
+            class C < String; end
+            S = C.new("bar")
+            def test(s) = s != S
+            test "foo"
+        "#);
+        assert_snapshot!(hir_string("test"), @r"
+        fn test@<compiled>:4:
+        bb0():
+          EntryPoint interpreter
+          v1:BasicObject = LoadSelf
+          v2:BasicObject = GetLocal l0, SP@4
+          Jump bb2(v1, v2)
+        bb1(v5:BasicObject, v6:BasicObject):
+          EntryPoint JIT(0)
+          Jump bb2(v5, v6)
+        bb2(v8:BasicObject, v9:BasicObject):
+          PatchPoint SingleRactorMode
+          PatchPoint StableConstantNames(0x1000, S)
+          v25:StringSubclass[VALUE(0x1008)] = Const Value(VALUE(0x1008))
+          PatchPoint MethodRedefined(String@0x1010, !=@0x1018, cme:0x1020)
+          PatchPoint NoSingletonClass(String@0x1010)
+          v29:StringExact = GuardType v9, StringExact
+          PatchPoint MethodRedefined(String@0x1010, ==@0x1048, cme:0x1050)
+          PatchPoint NoSingletonClass(String@0x1010)
+          v33:BoolExact = CCall v29, :String#==@0x1078, v25
+          v34:BoolExact = BoolNot v33
+          IncrCounter inline_cfunc_optimized_send_count
+          CheckInterrupts
+          Return v34
+        ");
+    }
+
     #[test]
     fn test_optimize_string_neq_nil() {
         eval(r#"