[llvm] [LLVM][LangRef] Redefine out-of-range stepvector values as being truncated. (PR #173494)

[Nikita Popov via llvm-commits]

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nikic wrote:

This comment is outdated now.

Why not drop the if entirely here instead of keeping the nullptr return?

https://github.com/llvm/llvm-project/pull/173494