Make liveness more precise for assignments to fields #73774
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Previously, we were too conservative and `x.field = 4` was treated as a "use" of `x`.
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r? @eddyb (rust_highfive has picked a reviewer for you, use r? to override) |
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| let mut x: (i32, i32) = (42, 0); | ||
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| // Assignment to a projection does not cause `x` to become live | ||
| unsafe { rustc_peek(x); } //~ ERROR bit not set |
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shouldn't this be after the assignment? Same with the read below
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Liveness propagates backwards, not forwards.
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r? @oli-obk |
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@bors r+ |
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…arth Rollup of 9 pull requests Successful merges: - rust-lang#73577 (Add partition_point) - rust-lang#73757 (Const prop: erase all block-only locals at the end of every block) - rust-lang#73774 (Make liveness more precise for assignments to fields) - rust-lang#73795 (Add some `const_compare_raw_pointers`-related regression tests) - rust-lang#73800 (Forward Hash::write_iN to Hash::write_uN) - rust-lang#73813 (Rename two `Resolver` traits) - rust-lang#73817 (Rename clashing_extern_decl to clashing_extern_declarations.) - rust-lang#73826 (Fix docstring typo) - rust-lang#73833 (Remove GlobalCtxt::enter_local) Failed merges: r? @ghost
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Previously, we were too conservative and
x.field = 4was treated as a "use" ofx. Now it neither killsx(since other fields ofxmay still be live) nor marks it as live.cc @jonas-schievink, who ran into this problem.