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Rollup of 18 pull requests #50611
Rollup of 18 pull requests #50611
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A previous PR fixed one method that was legitimately buggy; this cleans up the rest to be less diverse, mirroring the corresponding impls on [T] to the greatest extent possible without introducing any unnecessary UTF-8 boundary checks at 0.
GitHub users: I think you can add ?w=1 to the url for a vastly cleaner whitespace-ignoring diff
m*n lines of implementation deserves m*n lines of tests
Fixes rust-lang#50438. I'll make this more robust later for rust-lang#49815.
Because they are simple and hot. This change speeds up some incremental runs of a few rustc-perf benchmarks, the best by 3%.
This avoids a decent number of allocations, enough to speed up incremental runs of many rustc-benchmarks, the best by 2%.
This commit is spawned out of a performance regression investigation in rust-lang#50496. In tracking down this regression it turned out that the `expand_statements` function in the compiler was taking quite a long time. Further investigation showed two key properties: * The function was "fast" on glibc 2.24 and slow on glibc 2.23 * The hottest function was memmove from glibc Combined together it looked like glibc gained an optimization to the memmove function in 2.24. Ideally we don't want to rely on this optimization, so I wanted to dig further to see what was happening. The hottest part of `expand_statements` was `Drop for Drain` in the call to `splice` where we insert new statements into the original vector. This *should* be a cheap operation because we're draining and replacing iterators of the exact same length, but under the hood memmove was being called a lot, causing a slowdown on glibc 2.23. It turns out that at least one of the optimizations in glibc 2.24 was that `memmove` where the src/dst are equal becomes much faster. [This program][prog] executes in ~2.5s against glibc 2.23 and ~0.3s against glibc 2.24, exhibiting how glibc 2.24 is optimizing `memmove` if the src/dst are equal. And all that brings us to what this commit itself is doing. The change here is purely to `Drop for Drain` to avoid the call to `ptr::copy` if the region being copied doesn't actually need to be copied. For normal usage of just `Drain` itself this check isn't really necessary, but because `Splice` internally contains `Drain` this provides a nice speed boost on glibc 2.23. Overall this should fix the regression seen in rust-lang#50496 on glibc 2.23 and also fix the regression on Windows where `memmove` looks to not have this optimization. Note that the way `splice` was called in `expand_statements` would cause a quadratic number of elements to be copied via `memmove` which is likely why the tuple-stress benchmark showed such a severe regression. Closes rust-lang#50496 [prog]: https://gist.github.com/alexcrichton/c05bc51c6771bba5ae5b57561a6c1cd3
also make a drive-by typo fix
💔 Test failed - status-travis |
@bors: r+ |
📌 Commit a46d1dd has been approved by |
⌛ Testing commit a46d1ddc89d1a3a52d187fcd57c388a9283dd09e with merge e0f3a0a2cfa2e9245e425f1207c5d44118653563... |
💔 Test failed - status-travis |
The job Click to expand the log.
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The job Click to expand the log.
I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
Attempting to fix https://travis-ci.org/rust-lang/rust/jobs/377407894 via some selective ignoring tests
@bors: r+ Thanks tidy... |
📌 Commit 2c5d13d has been approved by |
Rollup of 18 pull requests Successful merges: - #49423 (Extend tests for RFC1598 (GAT)) - #50010 (Give SliceIndex impls a test suite of girth befitting the implementation (and fix a UTF8 boundary check)) - #50447 (Fix update-references for tests within subdirectories.) - #50514 (Pull in a wasm fix from LLVM upstream) - #50524 (Make DepGraph::previous_work_products immutable) - #50532 (Don't use Lock for heavily accessed CrateMetadata::cnum_map.) - #50538 ( Make CrateNum allocation more thread-safe. ) - #50564 (Inline `Span` methods.) - #50565 (Use SmallVec for DepNodeIndex within dep_graph.) - #50569 (Allow for specifying a linker plugin for cross-language LTO) - #50572 (Clarify in the docs that `mul_add` is not always faster.) - #50574 (add fn `into_inner(self) -> (Idx, Idx)` to RangeInclusive (#49022)) - #50575 (std: Avoid `ptr::copy` if unnecessary in `vec::Drain`) - #50588 (Move "See also" disambiguation links for primitive types to top) - #50590 (Fix tuple struct field spans) - #50591 (Restore RawVec::reserve* documentation) - #50598 (Remove unnecessary mutable borrow and resizing in DepGraph::serialize) - #50606 (Retry when downloading the Docker cache.) Failed merges: - #50161 (added missing implementation hint) - #50558 (Remove all reference to DepGraph::work_products)
☀️ Test successful - status-appveyor, status-travis |
Successful merges:
Span
methods. #50564 (InlineSpan
methods.)mul_add
is not always faster. #50572 (Clarify in the docs thatmul_add
is not always faster.)into_inner(self) -> (Idx, Idx)
to RangeInclusive (#49022) #50574 (add fninto_inner(self) -> (Idx, Idx)
to RangeInclusive (Tracking issue forstart
,end
andnew
methods of RangeInclusive #49022))ptr::copy
if unnecessary invec::Drain
#50575 (std: Avoidptr::copy
if unnecessary invec::Drain
)Failed merges: