[Mlir-commits] [mlir] [mlir][arith] Fix overflow bug in arith::CeilDivSIOp::fold (PR #90947)

[Mehdi Amini]

https://github.com/joker-eph approved this pull request.

This seems to me like it makes the folder strictly more conservative, which should be safe.

It is still open whether we couldn't be more aggressive though: are there cases where we could fold but we don't right now? (if so can you add a TODO? Possibly a test for these?) 
Can we accurately catch the real overflow cases and folds to poison for example? (arith may not generate poison out-of-thin air for now though)

https://github.com/llvm/llvm-project/pull/90947