Change the number of op results

MLIR
1

This is the source file.

%1 = scf.if %0 -> (i32) {
      %2 = arith.addi %arg1, %c1_i32 : i32
      scf.yield %2 : i32
    }

I write a pass process and get the following file.

%25 = "scf.if"(%23) ({
      %26 = "arith.addi"(%20, %13) : (i32, i32) -> i32
      %27 = "arith.cmpi"(%arg2, %0) {predicate = 0 : i64} : (i32, i32) -> i1
      %28 = "arith.cmpi"(%arg2, %0) {predicate = 1 : i64} : (i32, i32) -> i1
      %29 = "scf.if"(%27) ({
        "scf.yield"(%arg2) : (i32) -> ()
      }, {
        %30 = "arith.constant"() {value = -1 : i32} : () -> i32
        %31 = "arith.addi"(%arg2, %30) : (i32, i32) -> i32
        "scf.yield"(%31) : (i32) -> ()
      }) : (i1) -> i32
      "scf.yield"(%29, %26, %28) : (i32, i32, i1) -> ()
    }

error: ‘scf.if’ op region control flow edge from Region #0 to parent results: source has 3 operands, but target successor needs 1
Q:Because I’m inside a while loop and have some carry variables, I need to return two or three values. But the source file only supports one result, how can I change the number of Result?

2

My thought is builder.create an ifop and modify the TypeRange, but is there another way?

3

Yes, you must recreate the op if you are changing the number of results it has.