[SCF] Should `scf.for` support unsigned comparison?

MLIR
1

Please consider the following example:

func.func @foo() {
  %lb = arith.constant 0: i32
  %ub = arith.constant 0x80000001: i32
  %step = arith.constant 1: i32
  scf.for %iter = %lb to %ub step %step : i32 {
    "op.op"() : () -> ()
  }
  return
}

After canonicalization, the entire loop disappears. This is because scf.for strictly uses signed comparison for the bound calculation. See example here: Compiler Explorer

I’m wondering if there is a way to express this loop without using wider integer types or index types? In other words, should scf.for support unsigned comparison? The syntax can be something like

  scf.for unsigned %iter = %lb to %ub step %step : i32 {
    "op.op"() : () -> ()
  }