[llvm] [InstCombine] Return `nsw` when convert `shl` to `mul` if its on the RHS (PR #121671)

via llvm-commits llvm-commits at lists.llvm.org
Wed Jan 8 08:50:34 PST 2025


goldsteinn wrote:

> No strong opinion, but I'd leave this alone. The current code is obvious (we're just converting shl to mul and determine whether the mul has the nsw flag), while this would need some explanation for why it's okay to keep the nsw in one case but not the other.

I'm less concerned w/ keeping the `nsw` than performing the fold, but either way I doubt this shows up on opt benchmark so agreed its not priority.

https://github.com/llvm/llvm-project/pull/121671


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