tcg: Split out tcg_out_exit_tb

The INDEX_op_exit_tb opcode needs no register allocation.
Split out a dedicated helper function for it.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
diff --git a/tcg/i386/tcg-target.c.inc b/tcg/i386/tcg-target.c.inc
index 58bd587..feb257d 100644
--- a/tcg/i386/tcg-target.c.inc
+++ b/tcg/i386/tcg-target.c.inc
@@ -2347,6 +2347,17 @@
 #endif
 }
 
+static void tcg_out_exit_tb(TCGContext *s, uintptr_t a0)
+{
+    /* Reuse the zeroing that exists for goto_ptr.  */
+    if (a0 == 0) {
+        tcg_out_jmp(s, tcg_code_gen_epilogue);
+    } else {
+        tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_EAX, a0);
+        tcg_out_jmp(s, tb_ret_addr);
+    }
+}
+
 static inline void tcg_out_op(TCGContext *s, TCGOpcode opc,
                               const TCGArg args[TCG_MAX_OP_ARGS],
                               const int const_args[TCG_MAX_OP_ARGS])
@@ -2371,15 +2382,6 @@
     const_a2 = const_args[2];
 
     switch (opc) {
-    case INDEX_op_exit_tb:
-        /* Reuse the zeroing that exists for goto_ptr.  */
-        if (a0 == 0) {
-            tcg_out_jmp(s, tcg_code_gen_epilogue);
-        } else {
-            tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_EAX, a0);
-            tcg_out_jmp(s, tb_ret_addr);
-        }
-        break;
     case INDEX_op_goto_tb:
         if (s->tb_jmp_insn_offset) {
             /* direct jump method */
@@ -2794,6 +2796,7 @@
     case INDEX_op_mov_i32:  /* Always emitted via tcg_out_mov.  */
     case INDEX_op_mov_i64:
     case INDEX_op_call:     /* Always emitted via tcg_out_call.  */
+    case INDEX_op_exit_tb:  /* Always emitted via tcg_out_exit_tb.  */
     default:
         tcg_abort();
     }