[llvm] [Reassociate] Use uint64_t for repeat count (PR #94232)

[Nikita Popov via llvm-commits]

https://github.com/nikic approved this pull request.

LGTM. I initially thought we could cause overflow with an exponential tree like https://gist.github.com/nikic/e7736ce11aa66b75ac8fa2b0bf112537. But apparently this is not possible, because any value with multiple uses will be considered as a leaf. That means that the weights can only increase linearly and not exponentially.

https://github.com/llvm/llvm-project/pull/94232