2071ea24a2
We cannot infer more information from backedges in `solveBlockValueNonLocal`. However, since DT is unavailable in LVI, there is not a precise way to check whether a BB edge is a backedge. This patch only skips self loops to unblock the range analysis. The motivating case is extracted from https://github.com/llvm/llvm-project/pull/127663. Compile-time impact is high: https://llvm-compile-time-tracker.com/compare.php?from=84ddda58c870681dd12ed765e9d59d5e00567f94&to=af032f1351358f2f5b5d9f4e87c5601c23b9bd37&stat=instructions:u