[mlir][spirv] Retain nontemporal information when converting memref load/store

[antiagainst]

At the moment when we convert memref.load/memref.store we ignore the nontemporal attribute there. We should fix this to carry it to the spirv.Load/spirv.Store memory operands. And also make sure (de)serialization recognizes it.

[antiagainst]

@kuhar FYI

[llvmbot]

@llvm/issue-subscribers-mlir-spirv

Author: Lei Zhang (antiagainst)

At the moment when we convert `memref.load`/`memref.store` we ignore the `nontemporal` attribute there. We should fix this to carry it to the `spirv.Load`/`spirv.Store` memory operands. And also make sure (de)serialization recognizes it.

[llvmbot]

Hi!

This issue may be a good introductory issue for people new to working on LLVM. If you would like to work on this issue, your first steps are:

1. In the comments of the issue, request for it to be assigned to you.
2. Fix the issue locally.
3. Run the test suite locally. Remember that the subdirectories under test/ create fine-grained testing targets, so you can e.g. use make check-clang-ast to only run Clang's AST tests.
4. Create a Git commit.
5. Run git clang-format HEAD~1 to format your changes.
6. Open a pull request to the upstream repository on GitHub. Detailed instructions can be found in GitHub's documentation.

If you have any further questions about this issue, don't hesitate to ask via a comment in the thread below.

[llvmbot]

@llvm/issue-subscribers-good-first-issue

Author: Lei Zhang (antiagainst)

At the moment when we convert `memref.load`/`memref.store` we ignore the `nontemporal` attribute there. We should fix this to carry it to the `spirv.Load`/`spirv.Store` memory operands. And also make sure (de)serialization recognizes it.

[kuhar]

@antiagainst Since you marked this as 'good first issue', can you add a repro IR and mlir-opt invocation that shows where the nontemporal annotation get lost? I think this should make it much easier for newcomers to get started.

[antiagainst]

Right. Here is an input IR:

module attributes {
  spirv.target_env = #spirv.target_env<
    #spirv.vce<v1.0, [Shader], [SPV_KHR_storage_buffer_storage_class]>, #spirv.resource_limits<>>
} {

func.func @load_nontemporal(%arg0: memref<f32, #spirv.storage_class<StorageBuffer>>) {
  %0 = memref.load %arg0[] {nontemporal = true} : memref<f32, #spirv.storage_class<StorageBuffer>>
  memref.store %0, %arg0[] {nontemporal = true} : memref<f32, #spirv.storage_class<StorageBuffer>>
  return
}

}

With mlir-opt -convert-memref-to-spirv it should give:

spirv.Load "StorageBuffer" ... ["Nontemporal"] ..
spirv.Store "StorageBuffer" ... ["Nontemporal"] ...

For

spirv.module Logical GLSL450 requires #spirv.vce<v1.0, [Shader], []> {
  // CHECK-LABEL: spirv.func @load_store_memory_operands
  spirv.func @load_store_memory_operands(%arg0 : !spirv.ptr<f32, Input>, %arg1 : !spirv.ptr<f32, Output>) "None" {
    %1 = spirv.Load "Input" %arg0 ["Nontemporal|Volatile|Aligned", 4]: f32
    spirv.Store "Output" %arg1, %1 ["Nontemporal|Volatile|Aligned", 4]: f32
    spirv.Return
  }
}

with mlir-translate -no-implicit-module -test-spirv-roundtrip, it should get the same IR. (It should be the case at of right now; but need to update test to reflect it.)

[mvvsmk]

Hey I am new to MLIR, could you assign me this issue and I can begin hacking on it :)

[ranjanmangla1]

Hey @mvvsmk , Are you still working on it? I am new to LLVM & MLIR would love to take this issue!

[EugeneZelenko]

@ranjanmangla1: Just create pull request and mention it on this page.

[mvvsmk]

Hey @mvvsmk , Are you still working on it? I am new to LLVM & MLIR would love to take this issue!

Hey @ranjanmangla1 I am working on it, will create a PR soon :)

[antiagainst]

@ranjanmangla1 if you are interested, there are other issues that we can certainly use your help, please see https://github.com/llvm/llvm-project/issues?q=is%3Aopen+is%3Aissue+label%3Amlir%3Aspirv especially those ones with "good first issue" label. :)