Signed integer overflow is undefined behaviour in MSL. However, signed
integers are defined to be two's complement. This allows us to cast
signed values to their corresponding unsigned type, perform the
arithmetic on these unsigned values (which has defined overflow
behaviour) then cast the result back to signed.
Care must be taken when emitting the isign polyfill, which uses
metal::select(). We must ensure the -1, 0, and 1 literals used as
inputs to select() have the correct width, else bitcasting the output
of select() will fail due to mismatched widths.
* feat: Add 32-bit floating-point atomics
* Current supported platforms: Metal
* Platforms to support in the future: Vulkan
Related issues or PRs:
* gfx-rs/wgpu#1020
* Add changelog
* Edit changelog
* feat: Add 32-bit float atomics support for Vulkan (SPIR-V shaders)
* atomicSub for f32 in the previous commits is removed.
* Update test
* chore: doc type link
* refactor: Revise float atomics on msl and spv
* Make branches tidy
* Also revise old codes
* Ensure the implementations are supported by Metal and Vulkan backends
* refactor: Renaming flt32 atomics to float32 atomics
* chore: Add link to Vulkan feature
* fix: cargo fmt
* chore: hack comment
* Revert changelog
* Fix: Cargo advisory
* Update wgpu-hal/src/metal/adapter.rs
Co-authored-by: Teodor Tanasoaia <28601907+teoxoy@users.noreply.github.com>
* Update naga/src/lib.rs
Co-authored-by: Teodor Tanasoaia <28601907+teoxoy@users.noreply.github.com>
* Adjust feature flag position
---------
Co-authored-by: Teodor Tanasoaia <28601907+teoxoy@users.noreply.github.com>
The WGSL spec only allows named component expressions when the base
type is a vector or a structure, so this patch removes support for it
for matrices. Additionally tests which used this for matrices have
been updated to use indexing expressions instead, and a test has been
added to ensure a named component expression on a matrix results in an
error.
Apply automatic conversions to the right-hand sides of assignment and
compound assignment statements.
Fix `try_automatic_conversion_for_leaf_scalar` to handle arrays,
not just scalars, vectors, and matrices. Previously this was only used
for converting the right-hand sides of bit shift operators to `u32`,
and bit shift operators don't support arrays. But now we're using
`try_automatic_conversion_for_leaf_scalar` for ordinary assignments,
and you can assign arrays.
Update a test of propagating source code spans through compaction.
This test needs validation to report an error, but this commit's fix
causes the error in the test to be detected in the front end, which is
too early to exercise compaction. Use a new error that the front end
still won't notice.
Handle SPIR-V input that performs atomic operations on structs that
have more than one field. Track which fields of which struct types are
used by atomic operations on which global variables, and then give
those global variables new types in which exactly those fields have
had their `Scalar` leaf types changed to `Atomic`.
Add snapshot tests.
Co-authored-by: Jim Blandy <jimb@red-bean.com>
When lowering arguments for a user-defined function call, avoid
concretizing the argument types. Instead make use of the existing
`try_automatic_conversions()` machinery to attempt to convert each
argument to the type expected by the function. This is straightforward
as user-defined functions only have a single overload.
This additionally changes an argument type in the test
parse_pointers() from `ptr<private>` to `ptr<function>`. The former is
invalid code which is indeed caught by the validator, but the test
only asserts that parsing succeeds, not validation. With this patch,
this error is now caught during parsing which caused the test to fail.
Add support for parsing and executing OpAtomicCompareExchange in the SPIR-V frontend.
This concludes the work to support atomics in the SPIR-V frontend,
excluding test clean-up.
Fixes#6296.
Fixes#6590.
Connections:
- [naga spv-in] Support for OpAtomicCompareExchange #6296
- [spv-in] Atomics support #4489
Co-authored-by: Jim Blandy <jimb@red-bean.com>
We already lowered the function expression if it's a normal in argument; no need to do it again. This eliminates an unused variable and expression. With chained function calls, this could lead to a lot of waste.
There's still an extra unused expression in the case of an out/inout argument; ideally we'd remove these expressions, but it might be tricky.
Fixes#6602
Previously we only checked whether the outermost array's subtype was a
Matrix when determining whether to add ColMajor and MatrixStride
decorations, meaning arrays of arrays of matrices would not be
decorated.
In MSL output, avoid undefined behavior due to unbounded loops by
adding an unpredictable, never-actually-taken `break` to the bottom of
each loop body, rather than adding an unpredictable,
never-actually-taken branch over each loop.
This will probably have more of a performance impact, because it
affects each iteration of the loop, but unlike branching over the
loop, which leaves infinite loops (and thus undefined behavior) in the
output, this actually ensures that no loop presented to Metal is
unbounded, so that there is no undefined behavior present that the
optimizer could use to make unwelcome inferences.
Fixes#6528.
Until now we accepted a float, as is the case for non-depth textures.
This makes us compliant with the spec.
The validator is updated to expect an Sint or Uint when the ImageClass
is ImageClass::Depth. The SPIR-V frontend converts the LOD argument
from float to Sint (assuming that it is representable), likewise The
SPIR-V backend now converts the LOD from either Sint or Uint to
Float. HLSL and MSL backends require no changes as they implicitly do
that conversion. GLSL does not support non-compare LOD samples,
therefore no changes are required.
Implement WGSL frontend and WGSL, SPIR-V, HLSL, MSL, and GLSL
backends. WGSL and SPIR-V backends natively support the instruction.
MSL and HLSL emulate it by casting to f16 and back to f32. GLSL does
similar but must (mis)use (un)pack2x16 to do so.
