[PATCH] D86262: [LoopIdiomRecognizePass] Options to disable part or the entire Loop Idiom Recognize Pass

[Ettore Tiotto via Phabricator via llvm-commits]

etiotto accepted this revision.
etiotto added a comment.

Transforming a loop into a memset or memcpy is not always profitable (it depends on how many elements are initialized/copied and on the efficiency of the target architecture implementation for those libraries). The low level optimizer should change short memset/memcpy back into a sequence of assignments, IMO this should not be done in opt because the exact length for which memset is less profitable  than individual assignment is a function of the target architecture. As for this PR, adding an option to disable the optimization is a good thing as it provides more flexibility to users that for whatever reason do not want the transformation to run (and is also handy for compiler developers when debugging code). And more flexibility is a good thing.


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  https://reviews.llvm.org/D86262/new/

https://reviews.llvm.org/D86262