[Mlir-commits] [mlir] [mlir][BytecodeReader] Fix FusedLoc bytecode builder (PR #99632)

[Hideto Ueno]

uenoku wrote:

> How do you even get in this situation? And is intentional? (UnknownLoc wouldn't support FusedLoc metadata, so this isn't a lossless result of the builder).

CIRCT has a pass that drops specific locations (basically same as `mlir::StripDebugInfoPass` but CIRCT one takes a predicate). In that pass we use [`FusedLoc::get(MLIRContext*, ArrayRef<Location>, Attribute)` ](https://github.com/llvm/circt/blob/0102a610e92cf098a313c1fdc2b37156f5c04ff6/lib/Transforms/StripDebugInfoWithPred.cpp#L46)which could create fused location with empty or single location 

https://github.com/llvm/llvm-project/pull/99632