[Mlir-commits] [mlir] [MLIR][Arith] Fix index_cast/index_castui chain folding to check intermediate width (PR #189042)

[Scott Manley]

rscottmanley wrote:

> This is probably an OK fix, but I want to flag #183395 and #184876
> 
> The RFC for requiring `exact` on these folds and adding some flavor of `declare-index-bitwidth` pass / a mechanism for applying `exact` in the appropriate places in the code once you know your target index width is pending the person taking the lead on that getting back from vacation next week.

Also interested in this work. FIRToSCF / FIRToMemRef passes introduce this exact pattern *a lot* due to the `index` requirements of those dialects.



https://github.com/llvm/llvm-project/pull/189042