rust/library/core
Jacob Pratt 1ba9b7873a
Rollup merge of #138135 - scottmcm:chaining-ord, r=Mark-Simulacrum
Simplify `PartialOrd` on tuples containing primitives

We noticed in https://github.com/rust-lang/rust/pull/133984#issuecomment-2704011800 that currently the tuple comparison code, while it [does optimize down](https://github.com/rust-lang/rust/blob/master/tests/codegen/comparison-operators-2-tuple.rs) today, is kinda huge: <https://rust.godbolt.org/z/xqMoeYbhE>

This PR changes the tuple code to go through an overridable "chaining" version of the comparison functions, so that for simple things like `(i16, u16)` and `(f32, f32)` (as seen in the new MIR pre-codegen test) we just directly get the
```rust
if lhs.0 == rhs.0 { lhs.0 OP rhs.0 }
else { lhs.1 OP rhs.1 }
```
version in MIR, rather than emitting a mess for LLVM to have to clean up.

Test added in the first commit, so you can see the MIR diff in the second one.
2025-03-23 20:44:09 -04:00
..
src Rollup merge of #138135 - scottmcm:chaining-ord, r=Mark-Simulacrum 2025-03-23 20:44:09 -04:00
Cargo.toml Migrate core to Rust 2024 2025-03-11 09:46:34 -07:00