[Mlir-commits] [mlir] [mlir][scf] Extend fuse producer to multi-level candidates case (PR #97803)

[llvmlistbot at llvm.org]

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@@ -949,6 +949,145 @@ mlir::scf::tileAndFuseProducerOfSlice(
                                            tileAndFuseResult->tiledOps};
 }
 
+/// Get the real producer from candidate ExtractSliceOp
+///
+/// ```
+/// %0 = producer
+/// %1 = scf.for(%arg1 = %0)
+///   %2 = extract %arg1
+///   %3 = scf.for(%arg2 = %2)
+///      %4 = extract %args2
+///      ...
+/// ```
+///
+/// @param candidateSliceOp: %4 = extract %args2
+/// @param backwardSlice: in-out parameter populated by backward extractSliceOps
+/// @return OpResult Producer : %0 = producer
+static FailureOr<OpResult> getRealProducerFromExtractSliceOp(
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MaheshRavishankar wrote:

I am not sure this reasoning holds. If you want to fuse `%4` and not `%2` you are effectively "fusing" the slices and the doing the producer fusion. It would be better to stage it so that you fuse the slices so that you get the producer directly and then do the fusion. So effectively this change is trying to do both of this
1. Combine extract slices
2. Do producer fusion
in code. That is just added complexity. It would be easier to just combine the extract slices first and then fuse the producer.

https://github.com/llvm/llvm-project/pull/97803