GH-113464: Remove the extra jump via `_SIDE_EXIT` in `_EXIT_TRACE` (GH-118545)

4 files changed, 12 insertions, 29 deletions

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index e8383ed..ddada96 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -4133,7 +4133,7 @@ dummy_func(
         }
 
         tier2 op(_EXIT_TRACE, (--)) {
-            EXIT_IF(1);
+            EXIT_TO_TRACE();
         }
 
         tier2 op(_CHECK_VALIDITY, (--)) {
@@ -4266,10 +4266,6 @@ dummy_func(
             EXIT_TO_TIER1();
         }
 
-        tier2 op(_SIDE_EXIT, (--)) {
-            EXIT_TO_TRACE();
-        }
-
         tier2 op(_ERROR_POP_N, (target/2, unused[oparg] --)) {
             frame->instr_ptr = ((_Py_CODEUNIT *)_PyFrame_GetCode(frame)->co_code_adaptive) + target;
             SYNC_SP();
diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
index c3ee6e9..d0b794c 100644
--- a/Python/executor_cases.c.h
+++ b/Python/executor_cases.c.h
@@ -4127,10 +4127,7 @@
         }
 
         case _EXIT_TRACE: {
-            if (1) {
-                UOP_STAT_INC(uopcode, miss);
-                JUMP_TO_JUMP_TARGET();
-            }
+            EXIT_TO_TRACE();
             break;
         }
 
@@ -4319,11 +4316,6 @@
             break;
         }
 
-        case _SIDE_EXIT: {
-            EXIT_TO_TRACE();
-            break;
-        }
-
         case _ERROR_POP_N: {
             oparg = CURRENT_OPARG();
             uint32_t target = (uint32_t)CURRENT_OPERAND();
diff --git a/Python/optimizer.c b/Python/optimizer.c
index 56768ae..c0e1be9 100644
--- a/Python/optimizer.c
+++ b/Python/optimizer.c
@@ -976,7 +976,7 @@ count_exits(_PyUOpInstruction *buffer, int length)
     int exit_count = 0;
     for (int i = 0; i < length; i++) {
         int opcode = buffer[i].opcode;
-        if (opcode == _SIDE_EXIT || opcode == _DYNAMIC_EXIT) {
+        if (opcode == _EXIT_TRACE || opcode == _DYNAMIC_EXIT) {
             exit_count++;
         }
     }
@@ -1021,7 +1021,7 @@ prepare_for_execution(_PyUOpInstruction *buffer, int length)
         int32_t target = (int32_t)uop_get_target(inst);
         if (_PyUop_Flags[opcode] & (HAS_EXIT_FLAG | HAS_DEOPT_FLAG)) {
             uint16_t exit_op = (_PyUop_Flags[opcode] & HAS_EXIT_FLAG) ?
-                _SIDE_EXIT : _DEOPT;
+                _EXIT_TRACE : _DEOPT;
             int32_t jump_target = target;
             if (is_for_iter_test[opcode]) {
                 /* Target the POP_TOP immediately after the END_FOR,
@@ -1112,7 +1112,7 @@ sanity_check(_PyExecutorObject *executor)
                 CHECK(target_unused(opcode));
                 break;
             case UOP_FORMAT_EXIT:
-                CHECK(opcode == _SIDE_EXIT);
+                CHECK(opcode == _EXIT_TRACE);
                 CHECK(inst->exit_index < executor->exit_count);
                 break;
             case UOP_FORMAT_JUMP:
@@ -1138,9 +1138,9 @@ sanity_check(_PyExecutorObject *executor)
         uint16_t opcode = inst->opcode;
         CHECK(
             opcode == _DEOPT ||
-            opcode == _SIDE_EXIT ||
+            opcode == _EXIT_TRACE ||
             opcode == _ERROR_POP_N);
-        if (opcode == _SIDE_EXIT) {
+        if (opcode == _EXIT_TRACE) {
             CHECK(inst->format == UOP_FORMAT_EXIT);
         }
     }
@@ -1178,7 +1178,7 @@ make_executor_from_uops(_PyUOpInstruction *buffer, int length, const _PyBloomFil
         dest--;
         *dest = buffer[i];
         assert(opcode != _POP_JUMP_IF_FALSE && opcode != _POP_JUMP_IF_TRUE);
-        if (opcode == _SIDE_EXIT) {
+        if (opcode == _EXIT_TRACE) {
             executor->exits[next_exit].target = buffer[i].target;
             dest->exit_index = next_exit;
             dest->format = UOP_FORMAT_EXIT;
@@ -1398,14 +1398,13 @@ counter_optimize(
         return 0;
     }
     _Py_CODEUNIT *target = instr + 1 + _PyOpcode_Caches[JUMP_BACKWARD] - oparg;
-    _PyUOpInstruction buffer[5] = {
-        { .opcode = _START_EXECUTOR, .jump_target = 4, .format=UOP_FORMAT_JUMP },
+    _PyUOpInstruction buffer[4] = {
+        { .opcode = _START_EXECUTOR, .jump_target = 3, .format=UOP_FORMAT_JUMP },
         { .opcode = _LOAD_CONST_INLINE_BORROW, .operand = (uintptr_t)self },
         { .opcode = _INTERNAL_INCREMENT_OPT_COUNTER },
-        { .opcode = _EXIT_TRACE, .jump_target = 4, .format=UOP_FORMAT_JUMP },
-        { .opcode = _SIDE_EXIT, .target = (uint32_t)(target - _PyCode_CODE(code)), .format=UOP_FORMAT_TARGET }
+        { .opcode = _EXIT_TRACE, .target = (uint32_t)(target - _PyCode_CODE(code)), .format=UOP_FORMAT_TARGET }
     };
-    _PyExecutorObject *executor = make_executor_from_uops(buffer, 5, &EMPTY_FILTER);
+    _PyExecutorObject *executor = make_executor_from_uops(buffer, 4, &EMPTY_FILTER);
     if (executor == NULL) {
         return -1;
     }
diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h
index e680d76..b602d66 100644
--- a/Python/optimizer_cases.c.h
+++ b/Python/optimizer_cases.c.h
@@ -2140,10 +2140,6 @@
             break;
         }
 
-        case _SIDE_EXIT: {
-            break;
-        }
-
         case _ERROR_POP_N: {
             stack_pointer += -oparg;
             break;