target-m68k: fix gen_flush_flags()

gen_flush_flags() is setting unconditionally cc_op_synced to 1
and s->cc_op to CC_OP_FLAGS, whereas env->cc_op can be set
to something else by a previous tcg fragment.

We fix that by not setting cc_op_synced to 1
(except for gen_helper_flush_flags() that updates env->cc_op)

FIX: https://github.com/vivier/qemu-m68k/issues/19Signed-off-by: NLaurent Vivier <laurent@vivier.eu>
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Message-Id: <1484332593-16782-3-git-send-email-laurent@vivier.eu>

target/m68k/translate.c

@@ -595,18 +595,19 @@ static void gen_flush_flags(DisasContext *s)
 
     case CC_OP_DYNAMIC:
         gen_helper_flush_flags(cpu_env, QREG_CC_OP);
+        s->cc_op_synced = 1;
         break;
 
     default:
         t0 = tcg_const_i32(s->cc_op);
         gen_helper_flush_flags(cpu_env, t0);
         tcg_temp_free(t0);
+        s->cc_op_synced = 1;
         break;
     }
 
     /* Note that flush_flags also assigned to env->cc_op.  */
     s->cc_op = CC_OP_FLAGS;
-    s->cc_op_synced = 1;
 }
 
 static inline TCGv gen_extend(TCGv val, int opsize, int sign)