[llvm] [LSR] Reverse order in NarrowSearchSpaceByCollapsingUnrolledCode (PR #172314)

[Nikita Popov via llvm-commits]

nikic wrote:

> The Uses array is generated from IVUsers which places later uses earlier in the array.

As far as I can tell, IVUsers adds users in the order of the IR use list, which is not the same as the instruction order. The order of the use list is going to depend on exactly how the IR was created and how it was transformed.

I think whatever observation you have made here on the order is probably only true for freshly parsed textual IR. The uses would have to be explicitly sorted if the intent was to correspond to IR order.

https://github.com/llvm/llvm-project/pull/172314