Re: [PATCH v2] hw/rtc/twl92230: Silence warnings about missing fallthrough statements

[Markus Armbruster <armbru@redhat.com>]

Thomas Huth <thuth@redhat.com> writes:

> When compiling with -Werror=implicit-fallthrough, gcc complains about
> missing fallthrough annotations in this file. Looking at the code,
> the fallthrough is indeed wanted here, but instead of adding the
> annotations, it can be done more efficiently by simply calculating
> the offset with a subtraction instead of increasing a local variable
> one by one.
>
> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  v2: Fixed copy-n-paste bug
>
>  hw/rtc/twl92230.c | 50 +++++++++++++++++++++++------------------------
>  1 file changed, 24 insertions(+), 26 deletions(-)
>
> diff --git a/hw/rtc/twl92230.c b/hw/rtc/twl92230.c
> index f838913b37..50b97a1fce 100644
> --- a/hw/rtc/twl92230.c
> +++ b/hw/rtc/twl92230.c
> @@ -271,37 +271,36 @@ static void menelaus_gpio_set(void *opaque, int line, int level)
>  static uint8_t menelaus_read(void *opaque, uint8_t addr)
>  {
>      MenelausState *s = (MenelausState *) opaque;
> -    int reg = 0;
>  
>      switch (addr) {
>      case MENELAUS_REV:
>          return 0x22;
>  
> -    case MENELAUS_VCORE_CTRL5: reg ++;
> -    case MENELAUS_VCORE_CTRL4: reg ++;
> -    case MENELAUS_VCORE_CTRL3: reg ++;
> -    case MENELAUS_VCORE_CTRL2: reg ++;
> +    case MENELAUS_VCORE_CTRL5:
> +    case MENELAUS_VCORE_CTRL4:
> +    case MENELAUS_VCORE_CTRL3:
> +    case MENELAUS_VCORE_CTRL2:
>      case MENELAUS_VCORE_CTRL1:
> -        return s->vcore[reg];
> +        return s->vcore[addr - MENELAUS_VCORE_CTRL1];

Suggest to count up instead of down:

       case MENELAUS_VCORE_CTRL1:
  +    case MENELAUS_VCORE_CTRL2:
  +    case MENELAUS_VCORE_CTRL3:
  +    case MENELAUS_VCORE_CTRL4:
  +    case MENELAUS_VCORE_CTRL5:
  -        return s->vcore[reg];
  +        return s->vcore[addr - MENELAUS_VCORE_CTRL1];

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