[PATCH] D151644: [InstCombine] Propegating `nocapture` flag to callsites

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n added a comment.

@nikic think this should do it. I did assume that non-visible captures are okay. (I.e unused return value, or in your example provably dead-store).
The basic rule AFAICT is:
If the the callsite is in a returning basic-block, and between the callsite and the return there are only readonly instructions, then the capture state CANNOT change between the callsite and the return. Since at the return we KNOW the argument hasn't been captured, we can deduce that after the callsite (since it can't change after that) the pointer hasn't been captured.


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https://reviews.llvm.org/D151644