Re: [Qemu-devel] [RFC PATCH-for-4.1] target/i386: Correct misplaced break statement in gen_shiftd_rm_T1()

[Paolo Bonzini]

On 19/07/19 13:23, Philippe Mathieu-Daudé wrote:
> Reported by GCC9 when building with CFLAG -Wimplicit-fallthrough=2:
> 
>     CC      target/i386/translate.o
>   target/i386/translate.c: In function ‘gen_shiftd_rm_T1’:
>   target/i386/translate.c:1785:12: error: this statement may fall through 
> [-Werror=implicit-fallthrough=]
>    1785 |         if (is_right) {
>         |            ^
>   target/i386/translate.c:1810:5: note: here
>    1810 |     default:
>         |     ^~~~~~~
>   cc1: all warnings being treated as errors
> 
> Fixes: f437d0a3c24
> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
> ---
>  target/i386/translate.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/target/i386/translate.c b/target/i386/translate.c
> index 03150a86e2..4b2b5937ca 100644
> --- a/target/i386/translate.c
> +++ b/target/i386/translate.c
> @@ -1805,8 +1805,8 @@ static void gen_shiftd_rm_T1(DisasContext *s, TCGMemOp 
> ot, int op1,
>              tcg_gen_shri_i64(s->tmp0, s->tmp0, 32);
>              tcg_gen_shri_i64(s->T0, s->T0, 32);
>          }
> -        break;
>  #endif
> +        break;
>      default:
>          tcg_gen_subi_tl(s->tmp0, count, 1);
>          if (is_right) {
> 

I haven't looked closely at the code but I would guess that the
fallthrough is intended, because the default label has an "ot == MO_16"
condition.

It certainly needs more comments... :(

Paolo