use libm for acosh and asinh for f16, f32, and f64

[malezjaa]

Fixes #153878

Uses libm for acosh and asinh for f16, f32, and f64.
I didn't change impl for f128 as i couldn't find existing function for these in libm

[rustbot]

r? @joboet

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• Owners of files modified in this PR: @ChrisDenton, libs
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[reddevilmidzy]

Hello @malezjaa,
Next time you contribute, please check if someone has been assigned to the issue before contributing.

[malezjaa]

I'm really sorry about that. I should've checked If anyone was already assigned to this issue. I'll do that from now on.

[rustbot]

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[tgross35]

Happy to review this or alternatives, unless you have a preference @joboet

r? tgross35

[tgross35]

this fixes acosh and asinh for large float values using the approximation from libm

Can we just call libm via the cmath moule instead, rather than having the same logic here? Like we do for acos and similar.

Can you also clarify what approximations you are referencing? This isn't what is in https://github.com/rust-lang/compiler-builtins/blob/644346f0541f74fc425070f8e0712f2dac898e11/libm/src/math/acosh.rs.

[malezjaa]

Oh yeah that makes sense. I'll update the PR title and description to show that we're now using libm for these functions.
For f128 I kept the existing approximation since I couldn't find the f128 version in libm

[rust-log-analyzer]

The job x86_64-gnu-miri failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

tests/pass/shims/x86/rounding-error.rs ... ok
tests/pass/shims/x86/intrinsics-x86-gfni.rs ... ok

FAILED TEST: tests/pass/float.rs
command: MIRI_ENV_VAR_TEST="0" MIRI_TEMP="/tmp/miri-uitest-KeuWOb" RUST_BACKTRACE="1" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2-tools/x86_64-unknown-linux-gnu/release/miri" "--error-format=json" "--sysroot=/checkout/obj/build/x86_64-unknown-linux-gnu/miri-sysroot" "-Dwarnings" "-Dunused" "-Ainternal_features" "-Zui-testing" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2-tools/x86_64-unknown-linux-gnu/tmp/miri_ui/0/tests/pass" "tests/pass/float.rs" "--edition" "2021"

error: test got exit status: 1, but expected 0
 = note: compilation failed, but was expected to succeed

error: no output was expected
Execute `./miri test --bless` to update `tests/pass/float.stderr` to the actual output
+++ <stderr output>
error: unsupported operation: can't call foreign function `asinhf` on OS `linux`
##[error]  --> /checkout/library/std/src/num/f16.rs:835:9
   |
LL |         cmath::asinhf(self as f32) as f16
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ unsupported operation occurred here
   |
   = help: this means the program tried to do something Miri does not support; it does not indicate a bug in the program
   = note: stack backtrace:
           0: std::f16::<impl f16>::asinh
               at /checkout/library/std/src/num/f16.rs:835:9: 835:35
           1: libm
               at tests/pass/float.rs:1212:23: 1212:37
           2: main
               at tests/pass/float.rs:73:5: 73:11
---



full stderr:
error: unsupported operation: can't call foreign function `asinhf` on OS `linux`
##[error]  --> /checkout/library/std/src/num/f16.rs:835:9
   |
LL |         cmath::asinhf(self as f32) as f16
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ unsupported operation occurred here
   |
   = help: this means the program tried to do something Miri does not support; it does not indicate a bug in the program
   = note: stack backtrace:
           0: std::f16::<impl f16>::asinh
               at /checkout/library/std/src/num/f16.rs:835:9: 835:35
           1: libm
               at tests/pass/float.rs:1212:23: 1212:37
           2: main
               at tests/pass/float.rs:73:5: 73:11
---
Location:
   /cargo/registry/src/index.crates.io-1949cf8c6b5b557f/ui_test-0.30.3/src/lib.rs:365

  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ BACKTRACE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
   1: <color_eyre[fa244e63cbefe556]::config::EyreHook>::into_eyre_hook::{closure#0}<unknown>
      at <unknown source file>:<unknown line>
   2: <eyre[f23cdec6a3caa159]::Report>::from_adhoc::<&str><unknown>
      at <unknown source file>:<unknown line>
   3: ui_test[8296c1797d7c4a74]::run_tests_generic::<ui_test[8296c1797d7c4a74]::default_file_filter, ui[cebf951dc1980741]::run_tests::{closure#1}, alloc[ea442e7f9db0b120]::boxed::Box<dyn ui_test[8296c1797d7c4a74]::status_emitter::StatusEmitter>><unknown>
      at <unknown source file>:<unknown line>
   4: ui[cebf951dc1980741]::ui<unknown>
      at <unknown source file>:<unknown line>
   5: ui[cebf951dc1980741]::main<unknown>
      at <unknown source file>:<unknown line>
   6: std[5e094cc60be0206c]::sys::backtrace::__rust_begin_short_backtrace::<fn() -> core[c27f5559c9d72157]::result::Result<(), eyre[f23cdec6a3caa159]::Report>, core[c27f5559c9d72157]::result::Result<(), eyre[f23cdec6a3caa159]::Report>><unknown>
      at <unknown source file>:<unknown line>
   7: std[5e094cc60be0206c]::rt::lang_start::<core[c27f5559c9d72157]::result::Result<(), eyre[f23cdec6a3caa159]::Report>>::{closure#0}<unknown>
      at <unknown source file>:<unknown line>
   8: std[5e094cc60be0206c]::rt::lang_start_internal<unknown>
      at <unknown source file>:<unknown line>
   9: main<unknown>
      at <unknown source file>:<unknown line>
  10: __libc_start_main<unknown>
      at <unknown source file>:<unknown line>
  11: _start<unknown>
      at <unknown source file>:<unknown line>

Run with COLORBT_SHOW_HIDDEN=1 environment variable to disable frame filtering.
Run with RUST_BACKTRACE=full to include source snippets.
error: test failed, to rerun pass `--test ui`

Caused by:
  process didn't exit successfully: `/checkout/obj/build/x86_64-unknown-linux-gnu/stage2-tools/x86_64-unknown-linux-gnu/release/deps/ui-626f07652299b838` (exit status: 1)
Bootstrap failed while executing `test --stage 2 src/tools/miri src/tools/miri/cargo-miri`
Command `/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo test -Zwarnings --target x86_64-unknown-linux-gnu -Zbinary-dep-depinfo -j 4 -Zroot-dir=/checkout --locked --color=always --profile=release --manifest-path /checkout/src/tools/miri/Cargo.toml -- [workdir=/checkout]` failed with exit code 1
Created at: src/bootstrap/src/core/build_steps/tool.rs:191:21
Executed at: src/bootstrap/src/core/build_steps/test.rs:739:19

--- BACKTRACE vvv
   0: <bootstrap::utils::exec::DeferredCommand>::finish_process
             at /checkout/src/bootstrap/src/utils/exec.rs:939:17
   1: <bootstrap::utils::exec::DeferredCommand>::wait_for_output::<&bootstrap::utils::exec::ExecutionContext>
             at /checkout/src/bootstrap/src/utils/exec.rs:831:21
   2: <bootstrap::utils::exec::ExecutionContext>::run
             at /checkout/src/bootstrap/src/utils/exec.rs:741:45
   3: <bootstrap::utils::exec::BootstrapCommand>::run::<&bootstrap::core::builder::Builder>
             at /checkout/src/bootstrap/src/utils/exec.rs:339:27
   4: <bootstrap::core::build_steps::test::Miri as bootstrap::core::builder::Step>::run
             at /checkout/src/bootstrap/src/core/build_steps/test.rs:739:19
   5: <bootstrap::core::builder::Builder>::ensure::<bootstrap::core::build_steps::test::Miri>
             at /checkout/src/bootstrap/src/core/builder/mod.rs:1579:36
   6: <bootstrap::core::build_steps::test::Miri as bootstrap::core::builder::Step>::make_run
             at /checkout/src/bootstrap/src/core/build_steps/test.rs:665:21
   7: <bootstrap::core::builder::StepDescription>::maybe_run
             at /checkout/src/bootstrap/src/core/builder/mod.rs:476:13
   8: bootstrap::core::builder::cli_paths::match_paths_to_steps_and_run
             at /checkout/src/bootstrap/src/core/builder/cli_paths.rs:232:18
   9: <bootstrap::core::builder::Builder>::run_step_descriptions
             at /checkout/src/bootstrap/src/core/builder/mod.rs:1122:9
  10: <bootstrap::core::builder::Builder>::execute_cli
             at /checkout/src/bootstrap/src/core/builder/mod.rs:1101:14
  11: <bootstrap::Build>::build
             at /checkout/src/bootstrap/src/lib.rs:799:25
  12: bootstrap::main
             at /checkout/src/bootstrap/src/bin/main.rs:130:11
  13: <fn() as core::ops::function::FnOnce<()>>::call_once
             at /rustc/ad726b5063362ec9897ef3d67452fc5606ee70fa/library/core/src/ops/function.rs:250:5
  14: std::sys::backtrace::__rust_begin_short_backtrace::<fn(), ()>
             at /rustc/ad726b5063362ec9897ef3d67452fc5606ee70fa/library/std/src/sys/backtrace.rs:166:18
  15: std::rt::lang_start::<()>::{closure#0}
             at /rustc/ad726b5063362ec9897ef3d67452fc5606ee70fa/library/std/src/rt.rs:206:18
  16: <&dyn core::ops::function::Fn<(), Output = i32> + core::panic::unwind_safe::RefUnwindSafe + core::marker::Sync as core::ops::function::FnOnce<()>>::call_once
             at /rustc/ad726b5063362ec9897ef3d67452fc5606ee70fa/library/core/src/ops/function.rs:287:21
  17: std::panicking::catch_unwind::do_call::<&dyn core::ops::function::Fn<(), Output = i32> + core::panic::unwind_safe::RefUnwindSafe + core::marker::Sync, i32>
             at /rustc/ad726b5063362ec9897ef3d67452fc5606ee70fa/library/std/src/panicking.rs:581:40
  18: std::panicking::catch_unwind::<i32, &dyn core::ops::function::Fn<(), Output = i32> + core::panic::unwind_safe::RefUnwindSafe + core::marker::Sync>
             at /rustc/ad726b5063362ec9897ef3d67452fc5606ee70fa/library/std/src/panicking.rs:544:19
  19: std::panic::catch_unwind::<&dyn core::ops::function::Fn<(), Output = i32> + core::panic::unwind_safe::RefUnwindSafe + core::marker::Sync, i32>
             at /rustc/ad726b5063362ec9897ef3d67452fc5606ee70fa/library/std/src/panic.rs:359:14
  20: std::rt::lang_start_internal::{closure#0}
             at /rustc/ad726b5063362ec9897ef3d67452fc5606ee70fa/library/std/src/rt.rs:175:24
  21: std::panicking::catch_unwind::do_call::<std::rt::lang_start_internal::{closure#0}, isize>
             at /rustc/ad726b5063362ec9897ef3d67452fc5606ee70fa/library/std/src/panicking.rs:581:40
---
  28: __libc_start_main
  29: _start


Command has failed. Rerun with -v to see more details.
Build completed unsuccessfully in 0:37:57
  local time: Sat Mar 28 17:44:21 UTC 2026
  network time: Sat, 28 Mar 2026 17:44:21 GMT
##[error]Process completed with exit code 1.
##[group]Run echo "disk usage:"