python · Fidget-Spinner · Apr 14, 2026 · Apr 13, 2026 · Apr 13, 2026 · Apr 13, 2026
diff --git a/Lib/test/test_generated_cases.py b/Lib/test/test_generated_cases.py
@@ -2696,5 +2696,30 @@ def test_replace_opocode_uop_reject_array_effects(self):
                                    "Pure evaluation cannot take array-like inputs"):
            self.run_cases_test(input, input2, output)

+    def test_overridden_abstract_with_multiple_caches(self):
+        input = """
+        op(OP, (version/1, unused/1, index/1, value -- res)) {
+            res = SPAM(version, index, value);
+        }
+        """
+        input2 = """
+        op(OP, (value -- res)) {
+            res = eggs(version, index, value);
+        }
+        """
+        output = """
+        case OP: {
+            JitOptRef value;
+            JitOptRef res;
+            value = stack_pointer[-1];
+            uint16_t version = (uint16_t)this_instr->operand0;
+            uint16_t index = (uint16_t)this_instr->operand1;
+            res = eggs(version, index, value);
+            stack_pointer[-1] = res;
+            break;
+        }
+        """
+        self.run_cases_test(input, input2, output)
+
 if __name__ == "__main__":
    unittest.main()
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-04-13-16-52-33.gh-issue-148515.09xulC.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-04-13-16-52-33.gh-issue-148515.09xulC.rst
@@ -0,0 +1,2 @@
+Fix a bug in the JIT optimizer reading operands for uops with multiple
+caches.
diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h
@@ -412,14 +412,16 @@ def write_uop(
                    args.append(input.name)
            out.emit(f'DEBUG_PRINTF({", ".join(args)});\n')
        if override:
+            idx = 0
            for cache in uop.caches:
                if cache.name != "unused":
                    if cache.size == 4:
                        type = cast = "PyObject *"
                    else:
                        type = f"uint{cache.size*16}_t "
                        cast = f"uint{cache.size*16}_t"
-                    out.emit(f"{type}{cache.name} = ({cast})this_instr->operand0;\n")
+                    out.emit(f"{type}{cache.name} = ({cast})this_instr->operand{idx};\n")
+                    idx += 1
        if override:
            emitter = OptimizerEmitter(out, {}, uop, stack.copy())
            # No reference management of inputs needed.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Fix a bug in the JIT optimizer reading operands for uops with multiple
		caches.