interpreter: (pdl) fix multiple inserted operations in rewrite pattern interpreter

[jianyicheng]

(a + b) + c -> a + (b + c)

[superlopuh]

I would recommend doing a different approach to the one here: https://github.com/xdslproject/xdsl/pull/3402/files#diff-571b0c5cfc943738c6c960434941019e3e0fdc733da7c96dc242bd727e182ff6R402-R415

Instead, accumulating operations created in the pass to a work list, and adding them in the end, instead of getting them from a use-def chain at the end.

[superlopuh]

@cowardsa to provide example

[jumerckx]

builtin.module {
  pdl.pattern : benefit(1) {
    %x = pdl.operand
    %y = pdl.operand
    %z = pdl.operand
    %type = pdl.type
    %accumop = pdl.operation "arith.addi" (%x, %y : !pdl.value, !pdl.value) -> (%type : !pdl.type)
    %accum = pdl.result 0 of %accumop
    %resultop = pdl.operation "arith.addi" (%accum, %z : !pdl.value, !pdl.value) -> (%type : !pdl.type)
    %result = pdl.result 0 of %resultop

    pdl.rewrite %resultop {
      %newaccumop = pdl.operation "arith.addi" (%y, %z : !pdl.value, !pdl.value) -> (%type : !pdl.type)
      %newaccum = pdl.result 0 of %newaccumop

      %newresultop = pdl.operation "arith.addi" (%x, %newaccum : !pdl.value, !pdl.value) -> (%type : !pdl.type)
      %newresult = pdl.result 0 of %newresultop

      pdl.replace %accumop with %newaccumop
      pdl.replace %resultop with %newresultop
    }
  }
  func.func @impl() -> i32 {
    %a = arith.constant 3 : i32
    %a_1 = eqsat.eclass %a : i32
    %b = arith.constant 5 : i32
    %b_1 = eqsat.eclass %b : i32
    %c = arith.constant 7 : i32
    %c_1 = eqsat.eclass %c : i32
    %d = arith.addi %a_1, %b_1 : i32
    %d_1 = eqsat.eclass %d : i32
    %e = arith.addi %d_1, %c_1 : i32
    %e_1 = eqsat.eclass %e : i32
    func.return %e_1 : i32
  }
}

Looking into this issue, is this a test case where a rewrite should occur?

[superlopuh]

I'm not sure I understand your question, but my understanding is that the expected PDL pattern is only the last line, not the previous one, as the newresult will have the same value as result, and newaccumop will not have the same value as accumop.
Like if you have x = (a + b); y = x + c; y = x + 2, your rewrite would also rewrite x to b + c. But our current interpreter has a bug where the operations that are created in the pdl.rewrite are not inserted.