On 05/01/2022 14:34:39-0500, Hugo Villeneuve wrote:
> From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
>
> The rc variable doesn't need to be tested a second time when the <if> block
> evaluates to false.
>
rc is not tested a second time, here is the relevant listing:
- if (client->irq > 0)
+ if (client->irq > 0) {
ffffffff81aef647: 41 8b b5 bc 01 00 00 mov 0x1bc(%r13),%esi
ffffffff81aef64e: 85 f6 test %esi,%esi
ffffffff81aef650: 0f 8f 35 01 00 00 jg ffffffff81aef78b <isl1208_probe+0x314>
rc = isl1208_setup_irq(client, client->irq);
if (rc)
return rc;
+ }
- if (evdet_irq > 0 && evdet_irq != client->irq)
+ if (evdet_irq > 0 && evdet_irq != client->irq) {
ffffffff81aef656: 85 db test %ebx,%ebx
ffffffff81aef658: 7e 0d jle ffffffff81aef667 <isl1208_probe+0x1f0>
ffffffff81aef65a: 41 39 9d bc 01 00 00 cmp %ebx,0x1bc(%r13)
@@ -1663,6 +1664,7 @@ ffffffff81aef661: 0f 85 0a 01 00 00
rc = isl1208_setup_irq(client, evdet_irq);
if (rc)
return rc;
+ }
As you can see, no change in assembly but it is worse to read. gcc on
arm behaves the same way.
> Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
> ---
> drivers/rtc/rtc-isl1208.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/rtc/rtc-isl1208.c b/drivers/rtc/rtc-isl1208.c
> index 182dfa605515..c7f04df5a0b6 100644
> --- a/drivers/rtc/rtc-isl1208.c
> +++ b/drivers/rtc/rtc-isl1208.c
> @@ -880,15 +880,17 @@ isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
> if (rc)
> return rc;
>
> - if (client->irq > 0)
> + if (client->irq > 0) {
> rc = isl1208_setup_irq(client, client->irq);
> - if (rc)
> - return rc;
> + if (rc)
> + return rc;
> + }
>
> - if (evdet_irq > 0 && evdet_irq != client->irq)
> + if (evdet_irq > 0 && evdet_irq != client->irq) {
> rc = isl1208_setup_irq(client, evdet_irq);
> - if (rc)
> - return rc;
> + if (rc)
> + return rc;
> + }
>
> rc = devm_rtc_nvmem_register(isl1208->rtc, &isl1208->nvmem_config);
> if (rc)
> --
> 2.30.2
>
--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
