commit 0d9faa8cd5bbf335fd659710e5676d90d3bc5df3
author Steven Varoumas <steven.varoumas1@huawei.com> Mon Apr 22 13:54:01 2024 +0100
committer Copybara-Service <copybara-worker@google.com> Mon Apr 22 05:55:25 2024 -0700
tree b6661ff3256542a98b6407a66bafcc6d9eee6982
parent 895c0ecb54ecf0abc34a3fa6a7f6854b0d3efaf5

[mlir][Hoisting] Hoisting vector.extract/vector.broadcast pairs (#86108)

This transformation, inspired by what is done in
hoist_redundant_transfers, hoists pairs of extract/broadcast operations
out of scf.for loops.

It changes a loop of the form:

```
%res = scf.for _ = _ to _ step _ iter_args(%iarg = %v) -> (t1) {
  %e = vector.extract %iarg : t1 to t2
  %u = "some_use"(%e) : (t2) -> t2
  %b = vector.broadcast %u : t2 to t1
  scf.yield %b : t1
}
```

into the following:

```
%e = vector.extract %v: t1 to t2
%res' = scf.for _ = _ to _ step _ iter_args(%iarg = %e) -> (t2) {
  %u' = "some_use"(%iarg) : (t2) -> t2
  scf.yield %u' : t2
}
%res = vector.broadcast %res' : t2 to t1
```

GitOrigin-RevId: 35b292efc6fc31b884255d7cb46db7d6346c6f46