[naga hlsl-out, glsl-out] Support atomicCompareExchangeWeak #7658
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I don't see DXC doing anything with the |
| let fun_str = fun.to_hlsl_suffix(); | ||
| let compare_expr = match *fun { | ||
| crate::AtomicFunction::Exchange { compare: Some(cmp) } => Some(cmp), |
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We need to add cmp to need_bake_expressions to make sure that the expression chain doesn't get written multiple times. See crate::Statement::SubgroupCollectiveOperation for an example.
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Inserted cmp immediately after but let me know if there's a better place to do it
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Same comment as the GLSL backend, this should go in update_expressions_to_bake.
| // we just wrote `InterlockedAdd`, so negate the argument | ||
| write!(self.out, "-")?; | ||
| crate::AtomicFunction::Exchange { | ||
| compare: Some(compare_expr), |
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compare_expr needs to be added to need_bake_expressions.
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I added this logic directly here, but would it be better somewhere else like in update_expressions_to_bake?
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Yeah it should go in update_expressions_to_bake since it might be too late to register it here.
Connections
Fixes #7578
Fixes #4364
Description
Adds support for atomicCompareExchangeWeak translation to hlsl and glsl.
Note this does not implement the [allow_uav_condition] loop attribute mentioned here and here.
Not sure the best way to check if the loop termination is based off a UAV read.
Maybe can later borrow logic from the uniformity analyzer?
Dawn doesn't seem to do this either, though maybe it should?
There is a test with a while loop that depends on .exchanged which seems to pass hlsl validation.
Testing
Added / enabled some basic atomicCompareExchangeWeak tests to Naga.
My personal project using atomicCompareExchangeWeak runs fine now on Windows/Nvidia/DX12.
GL backend is untested outside the Naga tests / validation.
Squash or Rebase?
Squash
Checklist
cargo fmt.taplo format.cargo clippy --tests. If applicable, add:--target wasm32-unknown-unknowncargo xtask testto run tests.CHANGELOG.mdentry.