[all-commits] [llvm/llvm-project] 293064: [mlir] Add MemoryEffects::Allocate to memref::CloneOp

[Ivan Butygin via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 293064222a013055cda9240647110f5bcf8e1f31
      https://github.com/llvm/llvm-project/commit/293064222a013055cda9240647110f5bcf8e1f31
  Author: Butygin <ivan.butygin at intel.com>
  Date:   2021-06-29 (Tue, 29 Jun 2021)

  Changed paths:
    M mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp
    M mlir/test/Transforms/buffer-deallocation.mlir

  Log Message:
  -----------
  [mlir] Add MemoryEffects::Allocate to memref::CloneOp

Without it BufferDeallocationPass process only CloneOps created during pass itself and ignore all CloneOps that were already present in IR.

For our specific usecase:

```
func @dealloc_existing_clones(%arg0: memref<?x?xf64>, %arg1: memref<?x?xf64>) -> memref<?x?xf64> {
  return %arg0 : memref<?x?xf64>
}
```

Input arguments will be freed immediately after return from function and we want to prolong lifetime for the returned argument.
To achieve this we explicitly add clones to all input memrefs and expect that BufferDeallocationPass will add correct deallocs to them (unnessesary clone+dealloc pairs will be canonicalized away later).

Differential Revision: https://reviews.llvm.org/D104973