mirror of
https://github.com/rust-lang/rust.git
synced 2024-11-25 16:24:46 +00:00
7abab1efb2
Do array-slice equality via array equality, rather than always via slices ~~Draft because it needs a rebase after #91766 eventually gets through bors.~~ This enables the optimizations from #85828 to be used for array-to-slice comparisons too, not just array-to-array. For example, <https://play.rust-lang.org/?version=nightly&mode=release&edition=2021&gist=5f9ba69b3d5825a782f897c830d3a6aa> ```rust pub fn demo(x: &[u8], y: [u8; 4]) -> bool { *x == y } ``` Currently writes the array to stack for no reason: ```nasm sub rsp, 4 mov dword ptr [rsp], edx cmp rsi, 4 jne .LBB0_1 mov eax, dword ptr [rdi] cmp eax, dword ptr [rsp] sete al add rsp, 4 ret .LBB0_1: xor eax, eax add rsp, 4 ret ``` Whereas with the change in this PR it just compares it directly: ```nasm cmp rsi, 4 jne .LBB1_1 cmp dword ptr [rdi], edx sete al ret .LBB1_1: xor eax, eax ret ``` |
||
|---|---|---|
| .. | ||
| alloc | ||
| backtrace@b02ed04a7e | ||
| core | ||
| panic_abort | ||
| panic_unwind | ||
| portable-simd | ||
| proc_macro | ||
| profiler_builtins | ||
| rtstartup | ||
| rustc-std-workspace-alloc | ||
| rustc-std-workspace-core | ||
| rustc-std-workspace-std | ||
| std | ||
| stdarch@0716b22e90 | ||
| test | ||
| unwind | ||