They are used by integer formatting as well and is not exclusive to float.

In some projects (e.g. kernel), floating point is forbidden. They can disable
hardware floating point support and use `+soft-float` to avoid fp instructions
from being generated, but as libcore contains the formatting code for `f32`
and `f64`, some fp intrinsics are depended. One could define stubs for these
intrinsics that just panic [1], but it means that if any formatting functions
are accidentally used, mistake can only be caught during the runtime rather
than during compile-time or link-time, and they consume a lot of space without
LTO.

This patch provides an unstable cfg `no_fp_fmt_parse` to disable these.
A panicking stub is still provided for the `Debug` implementation (unfortunately)
because there are some SIMD types that use `#[derive(Debug)]`.

[1]: https://lkml.org/lkml/2021/4/14/1028

nbdd0121 changed the title core: add unstable no_floating_point to disable float formatting code core: add unstable no_fp_fmt_parse to disable float formatting code

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Dylan-DPC added a commit to Dylan-DPC/rust that referenced this pull request

`alloc`: add unstable cfg features `no_rc` and `no_sync`

In Rust for Linux we are using these to make `alloc` a bit more modular.

See rust-lang#86048 and rust-lang#84266 for similar requests.

Of course, the particular names are not important.

Dylan-DPC added a commit to Dylan-DPC/rust that referenced this pull request

`alloc`: add unstable cfg features `no_rc` and `no_sync`

In Rust for Linux we are using these to make `alloc` a bit more modular.

See rust-lang#86048 and rust-lang#84266 for similar requests.

Of course, the particular names are not important.

GKFX mentioned this pull request

thomcc pushed a commit to pgcentralfoundation/postgrestd that referenced this pull request

`alloc`: add unstable cfg features `no_rc` and `no_sync`

In Rust for Linux we are using these to make `alloc` a bit more modular.

See rust-lang/rust#86048 and rust-lang/rust#84266 for similar requests.

Of course, the particular names are not important.

github-actions bot pushed a commit to tautschnig/verify-rust-std that referenced this pull request

core: add unstable no_fp_fmt_parse to disable float formatting code

In some projects (e.g. kernel), floating point is forbidden. They can disable
hardware floating point support and use `+soft-float` to avoid fp instructions
from being generated, but as libcore contains the formatting code for `f32`
and `f64`, some fp intrinsics are depended. One could define stubs for these
intrinsics that just panic [1], but it means that if any formatting functions
are accidentally used, mistake can only be caught during the runtime rather
than during compile-time or link-time, and they consume a lot of space without
LTO.

This patch provides an unstable cfg `no_fp_fmt_parse` to disable these.
A panicking stub is still provided for the `Debug` implementation (unfortunately)
because there are some SIMD types that use `#[derive(Debug)]`.

[1]: https://lkml.org/lkml/2021/4/14/1028