[mlir] Question about RegionBranchOpInterface and scf.if

MLIR
1

I’m hitting crash in cleanRegionBranchOp when access region.front() or region.back() on mlir with scf.if which has empty else region like

func.func @nested_if(%cond0: i1, %cond1: i1, %cond2: i1, %p: memref<1xf32>) {
  %cst = arith.constant 1.000000e+00 : f32
  scf.if %cond0 {
  } else {
    scf.if %cond1 {
    } else {
      scf.if %cond2 {
        affine.store %cst, %p[0] : memref<1xf32>
      }
    }
  }
  return
}

There’s an assert at

assert(!region.empty() && "expected a non-empty region in an op "
                              "implementing `RegionBranchOpInterface`");

But scf.if is OK to have empty region as long as it doesn’t has result.

LogicalResult IfOp::verify() {
  if (getNumResults() != 0 && getElseRegion().empty())
    return emitOpError("must have an else block if defining values");
  return success();
}

Is it a bug to assert that ‘RegionBranchOpInterface’ cannot have an empty region?