RPCS3/llvm
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm.git synced 2024-12-03 01:12:53 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

[docs] Add a note on non-deterministic sorting order of equal elements

Browse Source 
Reviewers: RKSimon, t.p.northover, dexonsmith

Reviewed By: RKSimon

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D45831

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@330773 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Mandeep Singh Grang 2018-04-24 21:25:57 +00:00
parent ebab8e7d8d
commit 727ef0e543
1 changed files with 11 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
docs/CodingStandards.rst
View File

@ -826,6 +826,17 @@ As a rule of thumb, in case an ordered result is expected, remember to
sort an unordered container before iteration. Or use ordered containers
like vector/MapVector/SetVector if you want to iterate pointer keys.
Beware of non-deterministic sorting order of equal elements
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
std::sort uses a non-stable sorting algorithm in which the order of equal
elements is not guaranteed to be preserved. Thus using std::sort for a
container having equal elements may result in non-determinstic behavior.
To uncover such instances of non-determinism, LLVM has introduced a new
llvm::sort wrapper function. For an EXPENSIVE_CHECKS build this will randomly
shuffle the container before sorting. As a rule of thumb, always make sure to
use llvm::sort instead of std::sort.
Style Issues
============