[llvm-branch-commits] [llvm] release/18.x: [InstSimplify] Make sure the simplified value doesn't generate poison in threadBinOpOverSelect (#87075) (PR #88353)

[Yingwei Zheng via llvm-branch-commits]

dtcxzyw wrote:

> Hi @dtcxzyw (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix.

Fixed an incorrect poison-generating flag preservation in InstSimplify. It will fix a miscompilation on RISCV, which turns the incorrect `or disjoint` into an `add`.

Is that OK?

https://github.com/llvm/llvm-project/pull/88353