[PATCH] D123473: [LICM] Only create load in pre-header when promoting load.

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

> Maybe a better solution would be to clarify the wording for writeonly in langref to be clear that the attribute only considers writes to memory visible to its callers. Then we can retain writeonly even if loads to local objects are introduced. I doubt considering reads to function-local objects for writeonly adds any value.

These are already accepted semantics for memory attributes, see e.g. the code in checkFunctionMemoryAccess(), which ignores local memory. The wording in LangRef is "If a writeonly function reads memory visible to the program", which is a bit unclear, but probably the intent of "visible to the program" here is "visible to the caller".


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  https://reviews.llvm.org/D123473/new/

https://reviews.llvm.org/D123473