[PATCH] D123631: [InstCombine] Fold memrchr calls with sequences of identical bytes.

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

Just wondering if there's any specific motivation for this pattern, as it seems oddly specific. Is this something that GCC implements?



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Comment at: llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp:933
+  // C and N, fold memrchr(S, C, N) to
+  //   N != 0 && N <= sizeof S && *S == C ? S + N - 1 : null
+  // AKA
----------------
Why do we need the `N <= sizeof S` comparison here? As that would be UB, I think we can omit it here.


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  https://reviews.llvm.org/D123631/new/

https://reviews.llvm.org/D123631