Add 64 bit atomics #5383
Add 64 bit atomics #5383
Conversation
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@atlv24 Thanks very much for the new comments - these are helpful. |
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@atlv24 I just pushed a new commit to this branch; the log message is below. Could you look it over and see what you think?
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(No offense meant by removing your docs, after asking you to write them - they were helpful in getting started!) |
Rather than introducing an entirely new statement variant `AtomicNoResult`, make `Statement::Atomic::result` an `Option`. This reduces the patch size by about a third, and has no effect on snapshot output other than the direct IR dumps. In HLSL output, don't bother to generated "discard" temporaries for functions where the final `original_value` parameter is not required. This improves snapshot output. Improve documentation for `Expression::AtomicResult`, `Statement::Atomic`, and the new `valid::Capabilities` flags. Rewrite `Atomic` statement validation. Consolidate validation of `AtomicResult` expressions with this; gfx-rs#5771 ensures that there is indeed some `Atomic` statement referring to every `AtomicResult` expression, so we can be sure it will be validated. Fixes gfx-rs#5742.
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Merged trunk so CI would pay attention |
| mem::size_of::<crate::dx12::types::D3D12_FEATURE_DATA_D3D12_OPTIONS9>() as _, | ||
| ) | ||
| }; | ||
| hr == 0 && features9.AtomicInt64OnGroupSharedSupported != 0 |
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Shouldn't we check for AtomicInt64OnTypedResourceSupported as well?
| if let Some(ref shader_atomic_int64) = self.shader_atomic_int64 { | ||
| features.set( | ||
| F::SHADER_INT64_ATOMIC_ALL_OPS | F::SHADER_INT64_ATOMIC_MIN_MAX, | ||
| shader_atomic_int64.shader_buffer_int64_atomics != 0, |
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Shouldn't we check for shaderSharedInt64Atomics as well?
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shaderSharedInt64Atomicsindicates whether shaders can perform 64-bit unsigned and signed integer atomic operations on shared and payload memory.
Does "shared" mean WGSL var<workgroup>? What is "payload"?
/me searches the spec frantically
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Does "shared" mean WGSL
var<workgroup>?
That was my read, D3D12's AtomicInt64OnGroupSharedSupported is more explicit.
AtomicInt64OnGroupSharedSupportedis a boolean that specifies whether 64-bit integer atomics are supported ongroupsharedvariables.
What is "payload"?
I have no idea 😅
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I did not succeed in finding clearly relevant definitions of these terms.
Connections
Part of an incoming series of PRs needed by #5123
Others in this series: #5155 #5154
Addresses #4424
Depends on #5498 and #5497
Ultimately for bevy meshlets pipeline bevyengine/bevy#10164
Description
Shaders currently do not support 64 bit integer atomics. Add support for these gated by a feature flag when the capability is present.
Metal 64bit atomics are quite different from VK/DX style atomics, they do not have a return/output value of any kind and are only available in min/max variants. To accommodate this, a separate feature was added for min/max 64 bit atomics, and AtomicFunctionNoReturn was created in the naga IR to represent these return-less atomics.
DirectX ShaderModel version detection was also implemented, as SM 6.0 was insufficient for this feature.
Testing
A couple snapshot tests have been added to test int64 atomic operations.
Checklist
cargo fmt.cargo clippy. If applicable, add:--target wasm32-unknown-unknown--target wasm32-unknown-emscriptencargo xtask testto run tests.CHANGELOG.md. See simple instructions inside file.