compiler/utils/OrdList.hs · 18cb4f5e1b88aef7770446a354bfcc1e0a075e89 · Tobias Dammers / GHC

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6 years ago

Check for singletons when creating Bag/OrdList from a list. · 18cb4f5e

This gives us `One x` instead of `Many (x : [])` reducing overhead.
For compiling spectral/simple with -O0 difference was ~ -0.05%
allocations.

The only drawback is that something like toOL (x:panic "") will now
panic.  But that seems like a reasonable tradeoff.

Test Plan: ci, looking at +RTS -s

Reviewers: bgamari, jmct

Reviewed By: bgamari

Subscribers: jmct, rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4770

18cb4f5e

History

Check for singletons when creating Bag/OrdList from a list.

Andreas Klebinger authored 6 years ago

This gives us `One x` instead of `Many (x : [])` reducing overhead.
For compiling spectral/simple with -O0 difference was ~ -0.05%
allocations.

The only drawback is that something like toOL (x:panic "") will now
panic.  But that seems like a reasonable tradeoff.

Test Plan: ci, looking at +RTS -s

Reviewers: bgamari, jmct

Reviewed By: bgamari

Subscribers: jmct, rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4770

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