[Binding] Incorrect AffineIfOp condition

[chhzh123]

The current make_if facility in build_ir.py generates the following code (or similar to this one), which contains explicit comparison and cast operations, and cannot pass the MLIR verification.

#set = affine_set<(d0): (d0 - 1 == 0)>
module {
    func @kernel(%A: memref<1024xi32>) -> memref<1024xi32>
    {
        affine.for %i = 0 to 1024 {
            %zero = arith.constant 0 : i32
            %ii = arith.index_cast %i : index to i32
            %cond = arith.cmpi "sgt", %ii, %zero : i32
            %condi = arith.index_cast %cond : i1 to index
            affine.if #set(%condi) {
                %a = affine.load %A[%i] : memref<1024xi32>
                %add = arith.addi %a, %a: i32
                affine.store %add, %A[%i] : memref<1024xi32>
            }
        }
        return %A : memref<1024xi32>
    }
}

The verifier says

loc("../test/if.mlir":25:13): error: 'affine.if' op operand cannot be used as a dimension id

The correct way should be like

#set = affine_set<(d0): (d0 >= 0)>
module {
    func @kernel(%A: memref<1024xi32>) -> memref<1024xi32>
    {
        affine.for %i = 0 to 1024 {
            affine.if #set(%i) {
                %a = affine.load %A[%i] : memref<1024xi32>
                %add = arith.addi %a, %a: i32
                affine.store %add, %A[%i] : memref<1024xi32>
            }
        }
        return %A : memref<1024xi32>
    }
}

It needs to directly generate condition expression in the affine_set.