From 62303c16a52aaba51c24f14e68dea178e5c16fa8 Mon Sep 17 00:00:00 2001
From: Mark Shannon <mark@hotpy.org>
Date: Tue, 15 Feb 2022 09:35:16 +0000
Subject: [PATCH] bpo-46724: Use `JUMP_ABSOLUTE` for all backward jumps.
 (GH-31326)

(cherry picked from commit 3be1a443ca8e7d4ba85f95b78df5c4122cae9ede)
---
 .../2022-02-14-14-44-06.bpo-46724.jym_K6.rst                 | 2 ++
 Python/compile.c                                             | 5 +++++
 2 files changed, 7 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2022-02-14-14-44-06.bpo-46724.jym_K6.rst

diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-02-14-14-44-06.bpo-46724.jym_K6.rst b/Misc/NEWS.d/next/Core and Builtins/2022-02-14-14-44-06.bpo-46724.jym_K6.rst
new file mode 100644
index 00000000000000..7324182677abfd
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-02-14-14-44-06.bpo-46724.jym_K6.rst	
@@ -0,0 +1,2 @@
+Make sure that all backwards jumps use the ``JUMP_ABSOLUTE`` instruction, rather
+than ``JUMP_FORWARD`` with an argument of ``(2**32)+offset``.
diff --git a/Python/compile.c b/Python/compile.c
index a7f62bbcbb33e4..a8ace396b38484 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -6702,6 +6702,11 @@ assemble_emit(struct assembler *a, struct instr *i)
 }
 
 static void
+        if (last->i_opcode == JUMP_FORWARD) {
+            if (last->i_target->b_visited == 1) {
+                last->i_opcode = JUMP_ABSOLUTE;
+            }
+        }
 assemble_jump_offsets(struct assembler *a, struct compiler *c)
 {
     basicblock *b;