Reviewed-by: Karthikeyan Bhargavan <karthik.bhargavan@xxxxxxxxx>
> On 27 Jul 2020, at 17:08, Karthik Bhargavan <karthikeyan.bhargavan@xxxxxxxx> wrote:
>
> Removing unused variables is harmless. (GCC would do this automaticelly.)
> So this change seems fine.
>
> -Karthik
>
>> On 23 Jul 2020, at 12:05, Jason A. Donenfeld <jason@xxxxxxxxx> wrote:
>>
>> Hi Herbert,
>>
>> On Thu, Jul 23, 2020 at 9:51 AM Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:
>>>
>>> The carry variables are assigned but never used, which upsets
>>> the compiler. This patch removes them.
>>>
>>> Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
>>>
>>> diff --git a/arch/x86/crypto/curve25519-x86_64.c b/arch/x86/crypto/curve25519-x86_64.c
>>> index 8a17621f7d3a..8acbb6584a37 100644
>>> --- a/arch/x86/crypto/curve25519-x86_64.c
>>> +++ b/arch/x86/crypto/curve25519-x86_64.c
>>> @@ -948,10 +948,8 @@ static void store_felem(u64 *b, u64 *f)
>>> {
>>> u64 f30 = f[3U];
>>> u64 top_bit0 = f30 >> (u32)63U;
>>> - u64 carry0;
>>> u64 f31;
>>> u64 top_bit;
>>> - u64 carry;
>>> u64 f0;
>>> u64 f1;
>>> u64 f2;
>>> @@ -970,11 +968,11 @@ static void store_felem(u64 *b, u64 *f)
>>> u64 o2;
>>> u64 o3;
>>> f[3U] = f30 & (u64)0x7fffffffffffffffU;
>>> - carry0 = add_scalar(f, f, (u64)19U * top_bit0);
>>> + add_scalar(f, f, (u64)19U * top_bit0);
>>> f31 = f[3U];
>>> top_bit = f31 >> (u32)63U;
>>> f[3U] = f31 & (u64)0x7fffffffffffffffU;
>>> - carry = add_scalar(f, f, (u64)19U * top_bit);
>>> + add_scalar(f, f, (u64)19U * top_bit);
>>> f0 = f[0U];
>>> f1 = f[1U];
>>> f2 = f[2U];
>>> --
>>
>> That seems obvious and reasonable, and so I'm inclined to ack this,
>> but I first wanted to give Karthik (CC'd) a chance to chime in here,
>> as it's his HACL* project that's responsible, and he might have some
>> curious insight.
>>
>> Jason
>
