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| author | bors <bors@rust-lang.org> | 2024-07-12 20:36:43 +0000 |
|---|---|---|
| committer | bors <bors@rust-lang.org> | 2024-07-12 20:36:43 +0000 |
| commit | c6727fc9b5c64cefa7263486497ee95e529bd0f8 (patch) | |
| tree | 97a13f2f6b89c85feb20239b77a14958fea7083c /src/doc/rustc | |
| parent | 62c068feeafd1f4abbf87243d69cf8862e4dd277 (diff) | |
| parent | cae9d480bfe930a678fe2744082fc6ef1d957f63 (diff) | |
| download | rust-c6727fc9b5c64cefa7263486497ee95e529bd0f8.tar.gz rust-c6727fc9b5c64cefa7263486497ee95e529bd0f8.zip | |
Auto merge of #123351 - beetrees:x86-ret-snan-rust, r=nikic,workingjubilee
Ensure floats are returned losslessly by the Rust ABI on 32-bit x86 Solves #115567 for the (default) `"Rust"` ABI. When compiling for 32-bit x86, this PR changes the `"Rust"` ABI to return floats indirectly instead of in x87 registers (with the exception of single `f32`s, which this PR returns in general purpose registers as they are small enough to fit in one). No change is made to the `"C"` ABI as that ABI requires x87 register usage and therefore will need a different solution.
Diffstat (limited to 'src/doc/rustc')
| -rw-r--r-- | src/doc/rustc/src/platform-support.md | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/src/doc/rustc/src/platform-support.md b/src/doc/rustc/src/platform-support.md index f5cd4bd217a..370dbed50fa 100644 --- a/src/doc/rustc/src/platform-support.md +++ b/src/doc/rustc/src/platform-support.md @@ -41,10 +41,10 @@ target | notes `x86_64-pc-windows-msvc` | 64-bit MSVC (Windows 10+, Windows Server 2016+) `x86_64-unknown-linux-gnu` | 64-bit Linux (kernel 3.2+, glibc 2.17+) -[^x86_32-floats-return-ABI]: Due to limitations of the C ABI, floating-point support on `i686` targets is non-compliant: floating-point return values are passed via an x87 register, so NaN payload bits can be lost. See [issue #114479][x86-32-float-issue]. +[^x86_32-floats-return-ABI]: Due to limitations of the C ABI, floating-point support on `i686` targets is non-compliant: floating-point return values are passed via an x87 register, so NaN payload bits can be lost. Functions with the default Rust ABI are not affected. See [issue #115567][x86-32-float-return-issue]. [77071]: https://github.com/rust-lang/rust/issues/77071 -[x86-32-float-issue]: https://github.com/rust-lang/rust/issues/114479 +[x86-32-float-return-issue]: https://github.com/rust-lang/rust/issues/115567 ## Tier 1 @@ -209,6 +209,8 @@ target | std | notes [^x86_32-floats-x87]: Floating-point support on `i586` targets is non-compliant: the `x87` registers and instructions used for these targets do not provide IEEE-754-compliant behavior, in particular when it comes to rounding and NaN payload bits. See [issue #114479][x86-32-float-issue]. +[x86-32-float-issue]: https://github.com/rust-lang/rust/issues/114479 + [wasi-rename]: https://github.com/rust-lang/compiler-team/issues/607 [Fortanix ABI]: https://edp.fortanix.com/ |