From: Noam Cohen <noam@noam.me>
Date: Tue, 27 May 2025 18:30:17 +0000 (+0300)
Subject: gh-131798: Optimize `_ITER_CHECK_TUPLE` (GH-134803)
X-Git-Tag: v3.15.0a1~1485
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=79d81f7cba236e2cbdfa95d0de0a75ba9716ed32;p=thirdparty%2FPython%2Fcpython.git

gh-131798: Optimize `_ITER_CHECK_TUPLE` (GH-134803)
---

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-05-27-20-21-34.gh-issue-131798.b32zkl.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-05-27-20-21-34.gh-issue-131798.b32zkl.rst
new file mode 100644
index 000000000000..ed4b31bd7bed
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2025-05-27-20-21-34.gh-issue-131798.b32zkl.rst
@@ -0,0 +1 @@
+Allow the JIT to remove unnecessary ``_ITER_CHECK_TUPLE`` ops.
diff --git a/Python/optimizer_bytecodes.c b/Python/optimizer_bytecodes.c
index 34250fd4385d..e1209209660f 100644
--- a/Python/optimizer_bytecodes.c
+++ b/Python/optimizer_bytecodes.c
@@ -914,6 +914,13 @@ dummy_func(void) {
         }
     }
 
+    op(_ITER_CHECK_TUPLE, (iter, null_or_index -- iter, null_or_index)) {
+        if (sym_matches_type(iter, &PyTuple_Type)) {
+            REPLACE_OP(this_instr, _NOP, 0, 0);
+        }
+        sym_set_type(iter, &PyTuple_Type);
+    }
+
     op(_ITER_NEXT_RANGE, (iter, null_or_index -- iter, null_or_index, next)) {
        next = sym_new_type(ctx, &PyLong_Type);
     }
diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h
index bbd450671036..db86edcc7859 100644
--- a/Python/optimizer_cases.c.h
+++ b/Python/optimizer_cases.c.h
@@ -1615,6 +1615,12 @@
         }
 
         case _ITER_CHECK_TUPLE: {
+            JitOptSymbol *iter;
+            iter = stack_pointer[-2];
+            if (sym_matches_type(iter, &PyTuple_Type)) {
+                REPLACE_OP(this_instr, _NOP, 0, 0);
+            }
+            sym_set_type(iter, &PyTuple_Type);
             break;
         }