explain why shift with signed offset works the way it does #94659
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Some changes occured to the CTFE / Miri engine cc @rust-lang/miri |
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add extra tests for shifts with negative offsets Cc rust-lang/rust#94659
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| // zero-extended form). This matches the codegen backend: | ||
| // <https://github.com/rust-lang/rust/blob/f047af24b3b90f19b89fac80822acd69613b89ec/compiler/rustc_codegen_ssa/src/base.rs#L315-L317>. | ||
| // The overflow check is also ignorant to the sign: | ||
| // <https://github.com/rust-lang/rust/blob/8fae33d9b21e1e29da65506a2d6ac5bbbb3c4a86/compiler/rustc_codegen_ssa/src/mir/rvalue.rs#L728>. |
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I don't like permalinks too much in comments, especially two of them so close to each other but at different commits.
I don't have a good solution that won't cause the information to go stale though. At best we could have some soft of rustdoc link that will get complained about if it breaks and then link to the function in codegen.
Oh well, let's merge it, but please use the same commit id.
All right. |
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…askrgr Rollup of 3 pull requests Successful merges: - rust-lang#94659 (explain why shift with signed offset works the way it does) - rust-lang#94671 (fix pin doc typo) - rust-lang#94672 (Improved error message for failed bitcode load) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
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I was worried for a bit here that Miri/CTFE would be inconsistent with codegen, but I think everything is all right, actually.
Cc @oli-obk @eddyb