[PATCH] D87286: AArch64: make sure jump table entries can reach entire image

[Tim Northover via Phabricator via llvm-commits]

t.p.northover closed this revision.
t.p.northover added a comment.

> I'm a little concerned about the potential performance impact of the isNotDuplicable marking (that's the one change that impacts compressed jump tables), but your results seem to indicate it isn't significant.

I actually suspect that might be positive, or at least not as clear cut. The duplication code is pretty sensitive about the size of the sequence it duplicates, and doesn't know this expands to 3 real instructions (to even get the test working on simple code I had to increase the threshhold via a dev command-line option).

> Oh, that has limited range; I guess it doesn't help.

Yep, that's actually what started this whole saga (someone was obfuscating their code and ended up with a huge function with broken jump tables).

Anyway, thanks for the review. It's committed now as 2afe4becec7 <https://reviews.llvm.org/rG2afe4becec77d91b47afcc4b6eaaa1002cebf837>.


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https://reviews.llvm.org/D87286