[PATCH] D80911: AArch64+ARM: make LLVM consider system registers volatile to prevent unsound optimizations.

[Florian Hahn via Phabricator via llvm-commits]

fhahn added reviewers: fhahn, efriedma, hfinkel.
fhahn added a comment.

This seems similar to the problem described in https://bugs.llvm.org/show_bug.cgi?id=46210 : for intrinsics that are marked as reading memory, we do not account for the fact that the memory could be modified outside of the current program, which is what happens here.

The intrinsic seems like a good approach for addressing the issue for llvm.read_register incrementally. I guess there are other instances where we actually want ` llvm.read_volatile_register` on other platforms as well.


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https://reviews.llvm.org/D80911