Commit 018d8ac9 authored by Quentin Colombet's avatar Quentin Colombet
Browse files

[mlir][Vector] Fix a propagation bug with transfer_read

In the vector distribute patterns, we used to move
`vector.transfer_read`s out of `vector.warp_execute_on_lane0`s
irrespectively of how they were defined.

This could create transfer_read operations that would read values from
within the warpOp's body from outside of the body.
E.g.,
```
warpop {
  %defined_in_body
  %read = transfer_read %defined_in_body
  vector.yield %read
}
```
=>
```
warpop {
  %defined_in_body
  vector.yield ...
}
// %defined_in_body is referenced outside of its scope.
%read = transfer_read %defined_in_body
```

The fix consists in checking that all the values feeding the new
`transfer_read` are defined outside of warpOp's body.

Note: We could do this check before creating any operation, but that would
mean knowing what `affine::makeComposedAffineApply` actually do. So the
current fix is a trade off of coupling the implementations of this
propagation and `makeComposedAffineApply` versus compile time.

Differential Revision: https://reviews.llvm.org/D152149
parent 27aea17f
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment