ZJIT: Don't specialize calls with kwsplat (#15513)

Author: rwstauner

test/ruby/test_zjit.rb

@@ -626,6 +626,15 @@ def entry = test(e: :e, d: :d, c: :c, a: :a, b: :b)
     }, call_threshold: 2
   end
 
+  def test_send_kwsplat
+    assert_compiles '3', %q{
+      def test(a:) = a
+      def entry = test(**{a: 3})
+      entry
+      entry
+    }, call_threshold: 2
+  end
+
   def test_send_kwrest
     assert_compiles '{a: 3}', %q{
       def test(**kwargs) = kwargs

zjit/src/hir.rs

@@ -5229,6 +5229,7 @@ fn unspecializable_c_call_type(flags: u32) -> bool {
 /// If a given call uses overly complex arguments, then we won't specialize.
 fn unspecializable_call_type(flags: u32) -> bool {
     ((flags & VM_CALL_ARGS_SPLAT) != 0) ||
+    ((flags & VM_CALL_KW_SPLAT) != 0) ||
     ((flags & VM_CALL_ARGS_BLOCKARG) != 0)
 }
 

zjit/src/hir/opt_tests.rs

@@ -2993,6 +2993,33 @@ mod hir_opt_tests {
         ");
     }
 
+    #[test]
+    fn dont_specialize_call_to_iseq_with_call_kwsplat() {
+        eval("
+            def foo(a:) = a
+            def test = foo(**{a: 1})
+            test
+            test
+        ");
+        assert_snapshot!(hir_string("test"), @r"
+        fn test@<compiled>:3:
+        bb0():
+          EntryPoint interpreter
+          v1:BasicObject = LoadSelf
+          Jump bb2(v1)
+        bb1(v4:BasicObject):
+          EntryPoint JIT(0)
+          Jump bb2(v4)
+        bb2(v6:BasicObject):
+          v11:HashExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+          v12:HashExact = HashDup v11
+          IncrCounter complex_arg_pass_caller_kw_splat
+          v14:BasicObject = SendWithoutBlock v6, :foo, v12 # SendFallbackReason: Complex argument passing
+          CheckInterrupts
+          Return v14
+        ");
+    }
+
     #[test]
     fn dont_specialize_call_to_iseq_with_param_kwrest() {
         eval("