1 files changed, 4 insertions, 2 deletions
diff --git a/Python/ceval.c b/Python/ceval.c
index 12b0aef..a80583f 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1662,7 +1662,9 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
 #ifdef Py_STATS
     int lastopcode = 0;
 #endif
-    int opcode;        /* Current opcode */
+    // opcode is an 8-bit value to improve the code generated by MSVC
+    // for the big switch below (in combination with the EXTRA_CASES macro).
+    uint8_t opcode;        /* Current opcode */
     int oparg;         /* Current opcode argument, if any */
     _Py_atomic_int * const eval_breaker = &tstate->interp->ceval.eval_breaker;
 
@@ -5645,7 +5647,7 @@ handle_eval_breaker:
 #if USE_COMPUTED_GOTOS
         _unknown_opcode:
 #else
-        default:
+        EXTRA_CASES  // From opcode.h, a 'case' for each unused opcode
 #endif
             fprintf(stderr, "XXX lineno: %d, opcode: %d\n",
                     _PyInterpreterFrame_GetLine(frame),  opcode);