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89a18cb600
Like we have `add`/`sub` which are the `usize` version of `offset`, this adds the `usize` equivalent of `offset_from`. Like how `.add(d)` replaced a whole bunch of `.offset(d as isize)`, you can see from the changes here that it's fairly common that code actually knows the order between the pointers and *wants* a `usize`, not an `isize`. As a bonus, this can do `sub nuw`+`udiv exact`, rather than `sub`+`sdiv exact`, which can be optimized slightly better because it doesn't have to worry about negatives. That's why the slice iterators weren't using `offset_from`, though I haven't updated that code in this PR because slices are so perf-critical that I'll do it as its own change. This is an intrinsic, like `offset_from`, so that it can eventually be allowed in CTFE. It also allows checking the extra safety condition -- see the test confirming that CTFE catches it if you pass the pointers in the wrong order. |
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| .. | ||
| analyze_source_file | ||
| lev_distance | ||
| source_map | ||
| symbol | ||
| analyze_source_file.rs | ||
| caching_source_map_view.rs | ||
| def_id.rs | ||
| edition.rs | ||
| fatal_error.rs | ||
| hygiene.rs | ||
| lev_distance.rs | ||
| lib.rs | ||
| profiling.rs | ||
| source_map.rs | ||
| span_encoding.rs | ||
| symbol.rs | ||
| tests.rs | ||