From 2be4c370c6bfe98a85aa01c5d9c333b804d26197 Mon Sep 17 00:00:00 2001
From: Mark Shannon <mark@hotpy.org>
Date: Wed, 29 Sep 2021 13:16:13 +0100
Subject: Move predispatch logic from DISPATCH macro to juts before switch.
 Reduces size of each opocde in interpreter. (GH-28475)

---
 Python/ceval.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/Python/ceval.c b/Python/ceval.c
index 429ddb8..686250e 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1297,12 +1297,6 @@ eval_frame_handle_pending(PyThreadState *tstate)
 
 #if USE_COMPUTED_GOTOS
 #define TARGET(op) op: TARGET_##op
-#define DISPATCH_GOTO() goto *opcode_targets[opcode]
-#else
-#define TARGET(op) op
-#define DISPATCH_GOTO() goto dispatch_opcode
-#endif
-
 #define DISPATCH() \
     { \
         if (trace_info.cframe.use_tracing OR_DTRACE_LINE OR_LLTRACE) { \
@@ -1310,8 +1304,13 @@ eval_frame_handle_pending(PyThreadState *tstate)
         } \
         f->f_lasti = INSTR_OFFSET(); \
         NEXTOPARG(); \
-        DISPATCH_GOTO(); \
+        goto *opcode_targets[opcode]; \
     }
+#else
+#define TARGET(op) op
+#define DISPATCH() goto predispatch;
+#endif
+
 
 #define CHECK_EVAL_BREAKER() \
     if (_Py_atomic_load_relaxed(eval_breaker)) { \
@@ -1827,7 +1826,16 @@ main_loop:
             }
         }
 #endif
+#if USE_COMPUTED_GOTOS == 0
+    goto dispatch_opcode;
 
+    predispatch:
+        if (trace_info.cframe.use_tracing OR_DTRACE_LINE OR_LLTRACE) {
+            goto tracing_dispatch;
+        }
+        f->f_lasti = INSTR_OFFSET();
+        NEXTOPARG();
+#endif
     dispatch_opcode:
 #ifdef DYNAMIC_EXECUTION_PROFILE
 #ifdef DXPAIRS
-- 
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