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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 ``` |
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