[Mlir-commits] [mlir] [Tosa] : Fix integer overflow for computing intmax+1 in tosa.cast to linalg. (PR #112455)

[Sayan Saha]

sahas3 wrote:

Without the fix the IR after `tosa-to-linalg` for
```
func.func @test_cast_fp32_i64(%arg0: tensor<1xf32>) -> (tensor<1xi64>) {
  %0 = tosa.cast %arg0 : (tensor<1xf32>) -> tensor<1xi64>
  return %0: tensor<1xi64>
}
```
was 
``` 
#map = affine_map<(d0) -> (0)>
#map1 = affine_map<(d0) -> (d0)>
module {
  func.func @test_cast_fp32_i64(%arg0: tensor<1xf32>) -> tensor<1xui64> {
    %0 = tensor.empty() : tensor<1xi64>
    %1 = linalg.generic {indexing_maps = [#map, #map1], iterator_types = ["parallel"]} ins(%arg0 : tensor<1xf32>) outs(%0 : tensor<1xi64>) {
    ^bb0(%in: f32, %out: i64):
      %3 = math.roundeven %in : f32
      %cst = arith.constant -9.22337203E+18 : f32
      %cst_0 = arith.constant -9.22337203E+18 : f32
      %c9223372036854775807_i64 = arith.constant 9223372036854775807 : i64
      %4 = arith.maximumf %3, %cst : f32
      %5 = arith.fptosi %4 : f32 to i64
      %6 = arith.cmpf uge, %3, %cst_0 : f32
      %7 = arith.select %6, %c9223372036854775807_i64, %5 : i64
      linalg.yield %7 : i64
    } -> tensor<1xi64>
    %2 = builtin.unrealized_conversion_cast %1 : tensor<1xi64> to tensor<1xui64>
    return %2 : tensor<1xui64>
  }
}
```

https://github.com/llvm/llvm-project/pull/112455