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Specialize Iterator::try_fold and DoubleEndedIterator::try_rfold to improve code generation in all internal iteration scenarios. This changes brings the performance of internal iteration with RangeInclusive on par with the performance of iteration with Range: - Single conditional jump in hot loop, - Unrolling and vectorization, - And even Closed Form substitution. Unfortunately, it only applies to internal iteration. Despite various attempts at stream-lining the implementation of next and next_back, LLVM has stubbornly refused to optimize external iteration appropriately, leaving me with a choice between: - The current implementation, for which Closed Form substitution is performed, but which uses 2 conditional jumps in the hot loop when optimization fail. - An implementation using a "is_done" boolean, which uses 1 conditional jump in the hot loop when optimization fail, allowing unrolling and vectorization, but for which Closed Form substitution fails. In the absence of any conclusive evidence as to which usecase matters most, and with no assurance that the lack of Closed Form substitution is not indicative of other optimizations being foiled, there is no way to pick one implementation over the other, and thus I defer to the statu quo as far as next and next_back are concerned.
Co-Authored-By: oli-obk <github35764891676564198441@oli-obk.de>
It is currently a method of `Token`, but it only is valid to call if `self` is a `Token::Interpolated`. This commit eliminates the possibility of misuse by changing it to an associated function that takes a `Nonterminal`, which also simplifies the call sites. This requires splitting out a new function, `nonterminal_to_string`.
It's present within `Token::Interpolated` as an optimization, so that if a nonterminal is converted to a `TokenStream` multiple times, the first-computed value is saved and reused. But in practice it's not needed. `interpolated_to_tokenstream()` is a cold function: it's only called a few dozen times while compiling rustc itself, and a few hundred times across the entire `rustc-perf` suite. Furthermore, when it is called, it is almost always the first conversion, so no benefit is gained from it. So this commit removes `LazyTokenStream`, along with the now-unnecessary `Token::interpolated()`. As well as a significant simplification, the removal speeds things up slightly, mostly due to not having to `drop` the `LazyTokenStream` instances.
The current code (expensively) clones the value within an `Rc`. This commit changes things so that the `Rc` itself is (cheaply) cloned instead, avoid some allocations. This requires converting a few `Rc` instances to `Lrc`.
These are probably leftovers from recent `TokenStream` simplifications.
We can now use `?`
…r=Centril Deny the `overflowing_literals` lint for all editions The `overflowing_literals` was made deny by default for the 2018 edition by rust-lang#54507, however I'm not aware of any reason it can't be made deny by default for the 2015 edition as well.
…r=SimonSapin Deprecate the unstable Vec::resize_default As a way to either get additional feedback to stabilize or help move nightly users off it. Tracking issue: rust-lang#41758 (comment) r? @SimonSapin
Wrap write_bytes in a function. Move docs This will allow us to add debug assertions. See issue rust-lang#53871.
deprecate before_exec in favor of unsafe pre_exec Fixes rust-lang#39575 As per the [lang team decision](rust-lang#39575 (comment)): > The language team agreed that before_exec should be unsafe, and leaves the details of a transition plan to the libs team. Cc @alexcrichton @rust-lang/libs how would you like to proceed?
RangeInclusive internal iteration performance improvement. Specialize `Iterator::try_fold` and `DoubleEndedIterator::try_rfold` to improve code generation in all internal iteration scenarios. This changes brings the performance of internal iteration with `RangeInclusive` on par with the performance of iteration with `Range`: - Single conditional jump in hot loop, - Unrolling and vectorization, - And even Closed Form substitution. Unfortunately, it only applies to internal iteration. Despite various attempts at stream-lining the implementation of `next` and `next_back`, LLVM has stubbornly refused to optimize external iteration appropriately, leaving me with a choice between: - The current implementation, for which Closed Form substitution is performed, but which uses 2 conditional jumps in the hot loop when optimization fail. - An implementation using a `is_done` boolean, which uses 1 conditional jump in the hot loop when optimization fail, allowing unrolling and vectorization, but for which Closed Form substitution fails. In the absence of any conclusive evidence as to which usecase matters most, and with no assurance that the lack of Closed Form substitution is not indicative of other optimizations being foiled, there is no way to pick one implementation over the other, and thus I defer to the statu quo as far as `next` and `next_back` are concerned.
…s-surrounding-lifetimes, r=estebank Suggest removing parentheses surrounding lifetimes Fixes rust-lang#57386. r? @estebank
…nts, r=arielb1 Check the Self-type of inherent associated constants r? @arielb1
…etrochenkov Remove `LazyTokenStream`. `LazyTokenStream` was added in rust-lang#40939. Perhaps it was an effective optimization then, but no longer. This PR removes it, making the code both simpler and faster. r? @alexcrichton
Const to op simplification r? @RalfJung alternative to rust-lang#58486
Add a note about 2018e if someone uses `try {` in 2015e
Inspired by rust-lang#58491, where a `try_blocks` example was accidentally run in 2015, which of course produces a bunch of errors.
What's the philosophy about gating for this? The keyword is stably a keyword in 2018, so I haven't gated it for now but am not mentioning what the keyword _does_. Let me know if I should do differently.
remove a bit of dead code [Six years](rust-lang@5dc5efe) seem to be a long enough transition period 🤣
cleanup macro after 2018 transition We can now use `?`
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@bors r+ p=12 |
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📌 Commit 343fd19 has been approved by |
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⌛ Testing commit 343fd19 with merge aa00d21893c0d0201780e655e217d1644be7d787... |
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💔 Test failed - checks-travis |
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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 |
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Successful merges:
overflowing_literalslint for all editions #55632 (Deny theoverflowing_literalslint for all editions)LazyTokenStream. #58476 (RemoveLazyTokenStream.)try {in 2015e #58555 (Add a note about 2018e if someone usestry {in 2015e)Failed merges:
r? @ghost