[llvm] [clang] [InstCombine] Infer disjoint flag on Or instructions. (PR #72912)

[Nikita Popov via cfe-commits]

nikic wrote:

> We don't have a `isGuaranteedNotToBeUndef` only function, so that's the only way. I would leave a fixme, since this call can be removed if we ever manage to kill undef.

I actually added this function earlier today.

> @nikic is something like this the right fix?

I'd move the calls to isGuaranteedNotToBeUndef into haveNoCommonBitsSetSpecialCases, so you can check the correct values.


https://github.com/llvm/llvm-project/pull/72912