[llvm] [SimplifyCFG] Use context instruction in foldBranchToCommonDest() (PR #203516)

[Nikita Popov via llvm-commits]

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nikic wrote:

This was a good call. It turns out that we have another bug in the KnowlegeRetention framework:
https://github.com/llvm/llvm-project/blob/d038850fde42c69028b84135437cb2be994d0ada/llvm/lib/Analysis/AssumeBundleQueries.cpp#L109-L114 This falls back to value 1 for non-constants, which is correct for assumes, but incorrect for dereferenceable. I guess we just didn't test the specific case of 1 byte dereferenceability anywhere else...

https://github.com/llvm/llvm-project/pull/203516