GH-100110: Specialize FOR_ITER for tuples (GH-100109)

* Specialize FOR_ITER for tuples

1 files changed, 23 insertions, 0 deletions

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 7a1bfdc..5807bd5 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -2524,6 +2524,29 @@ dummy_func(
         }
 
         // stack effect: ( -- __0)
+        inst(FOR_ITER_TUPLE) {
+            assert(cframe.use_tracing == 0);
+            _PyTupleIterObject *it = (_PyTupleIterObject *)TOP();
+            DEOPT_IF(Py_TYPE(it) != &PyTupleIter_Type, FOR_ITER);
+            STAT_INC(FOR_ITER, hit);
+            PyTupleObject *seq = it->it_seq;
+            if (seq) {
+                if (it->it_index < PyTuple_GET_SIZE(seq)) {
+                    PyObject *next = PyTuple_GET_ITEM(seq, it->it_index++);
+                    PUSH(Py_NewRef(next));
+                    JUMPBY(INLINE_CACHE_ENTRIES_FOR_ITER);
+                    goto end_for_iter_tuple;  // End of this instruction
+                }
+                it->it_seq = NULL;
+                Py_DECREF(seq);
+            }
+            STACK_SHRINK(1);
+            Py_DECREF(it);
+            JUMPBY(INLINE_CACHE_ENTRIES_FOR_ITER + oparg + 1);
+        end_for_iter_tuple:
+        }
+
+        // stack effect: ( -- __0)
         inst(FOR_ITER_RANGE) {
             assert(cframe.use_tracing == 0);
             _PyRangeIterObject *r = (_PyRangeIterObject *)TOP();