[PATCH] D69387: [ConstantRange] Add toKnownBits() method

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D69387#1722346 <https://reviews.llvm.org/D69387#1722346>, @nikic wrote:

> So, this looks fine, but I'm still not quite clear on the use-case. I thought this might be useful for computing ranges of bit ops, but now that I see the implementation, I don't think that's the case. We just get the known top bits, but lose any information about the low bits (which can still be used, though in an operation-specific manner).
>
> We should probably have some case where we can actually use this before landing.


Would we not be better-off using this rather than whatever conservative implementation we currently have for `binaryAnd()`/`binaryOr()`/`binaryXor()`?


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https://reviews.llvm.org/D69387