[llvm] [InstCombine] Fold negation of unsigned div of non-negatives (PR #84951)

[via llvm-commits]

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@@ -2062,6 +2062,26 @@ static Instruction *foldSubOfMinMax(BinaryOperator &I,
   return nullptr;
 }
 
+/// Fold `sub 0, (udiv nneg X, nneg C)` into `sdiv nneg X, -C`
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goldsteinn wrote:

I don't think so, in that case you aren't saving any instructions and basically just throwing out `exact` and doing `udiv`-> `sdiv`. Both of which alone are not profitable.

https://github.com/llvm/llvm-project/pull/84951