Re: [PATCH] crypto: ecc - Optimize vli additive operations using compiler builtins

[Stefan Berger]

On 6/7/26 7:24 AM, Fabian Blatter wrote:
> Replace the software carry flag emulation with compiler builtins.
>
> Even the newest compilers struggle with taking advantage of the
> hardware carry flag. Compiler builtins allow the compiler to
> much more easily achieve this while still remaining constant-time.
>
> This yields an approximately 6-7% performance improvement
> on the ecc_gen_privkey, ecc_make_pub_key and crypto_ecdh_shared_secret
> functions on x86_64 on all curve sizes.
>
> Additionally, the code becomes much more readable.
>
> Signed-off-by: Fabian Blatter <fabianblatter09@xxxxxxxxx>

Reviewed-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>