[Mlir-commits] [mlir] [mlir][ArmSME] Use liveness information in the tile allocator (PR #90448)

[Andrzej Warzyński]

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banach-space wrote:

Something like this:
```mlir
  func.func @simple_branch(%arg0: vector<[4]x[4]xf32>) {
    cf.br ^bb1
  ^bb1:  // 2 preds: ^bb0, ^bb4
    "test.some_use"(%arg0) : (vector<[4]x[4]xf32>) -> ()
  ^bb2:  // no predecessors
    %0 = arm_sme.get_tile : vector<[4]x[4]xf32>
    cf.br ^bb3
  ^bb3:  // pred: ^bb2
    "test.some_use"(%0) : (vector<[4]x[4]xf32>) -> ()
  ^bb4:  // no predecessors
    cf.br ^bb1
  ^bb5:  // no predecessors
    return
  }
```

That's one edge case that's not being tested ATM. IIUC, no copies should be happening here. 

https://github.com/llvm/llvm-project/pull/90448