Rolling up PRs in the queue#12221
Closed
alexcrichton wants to merge 8 commits intorust-lang:masterfrom
Closed
Conversation
Externally loaded libraries are able to do things that cause references to them to survive past the expansion phase (e.g. creating @-box cycles, launching a task or storing something in task local data). As such, the library has to stay loaded for the lifetime of the process.
::num::bigint, Remove a source of O(n^2) running time in `fn shr_bits`. I'll cut to the chase: On my laptop, this brings the running time on `pidigits 2000` (from src/test/bench/shootout-pidigits.rs) from this: ``` % time ./pidigits 2000 > /dev/null real 0m7.695s user 0m7.690s sys 0m0.005s ``` to this: ``` % time ./pidigits 2000 > /dev/null real 0m0.322s user 0m0.318s sys 0m0.004s ``` The previous code was building up a vector by repeatedly making a fresh copy for each element that was unshifted onto the front, yielding quadratic running time. This fixes that by building up the vector in reverse order (pushing elements onto the end) and then reversing it. (Another option would be to build up a zero-initialized vector of the desired length and then installing all of the shifted result elements into their target index, but this was easier to hack up quickly, and yields the desired asymptotic improvement. I have been thinking of adding a `vec::from_fn_rev` to handle this case, maybe I will try that this weekend.)
Member
Author
|
Perhaps another time. |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
9 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Closes #12167
Closes #12200
Closes #12206
Closes #12209
Closes #12210
Closes #12211
Closes #12217
Closes #12218