From: neonene <53406459+neonene@users.noreply.github.com>
Date: Thu, 30 Jun 2022 15:38:29 +0000 (+0900)
Subject: gh-91719: Reload opcode on unknown error so that C can optimize the dispatching in... 
X-Git-Tag: v3.12.0a1~1062
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ea39b77de9fa25b447d0b4148f75f351076e890a;p=thirdparty%2FPython%2Fcpython.git

gh-91719: Reload opcode on unknown error so that C can optimize the dispatching in ceval.c (#94364)
---

diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-06-29-22-18-36.gh-issue-91719.3APYYI.rst b/Misc/NEWS.d/next/Core and Builtins/2022-06-29-22-18-36.gh-issue-91719.3APYYI.rst
new file mode 100644
index 000000000000..0d085e887783
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-06-29-22-18-36.gh-issue-91719.3APYYI.rst	
@@ -0,0 +1,2 @@
+Reload ``opcode`` when raising ``unknown opcode error`` in the interpreter main loop,
+for C compilers to generate dispatching code independently.
diff --git a/Python/ceval.c b/Python/ceval.c
index 946e997fc832..4fcdf9b41dea 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -5706,6 +5706,9 @@ handle_eval_breaker:
 #else
         EXTRA_CASES  // From opcode.h, a 'case' for each unused opcode
 #endif
+            /* Tell C compilers not to hold the opcode variable in the loop.
+               next_instr points the current instruction without TARGET(). */
+            opcode = _Py_OPCODE(*next_instr);
             fprintf(stderr, "XXX lineno: %d, opcode: %d\n",
                     _PyInterpreterFrame_GetLine(frame),  opcode);
             _PyErr_SetString(tstate, PyExc_SystemError, "unknown opcode");