Replace incorrect, UB-prone fptoui_sat with a corret implementation.#287
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FractalFir merged 1 commit intoRust-GPU:mainfrom Oct 5, 2025
Merged
Replace incorrect, UB-prone fptoui_sat with a corret implementation.#287FractalFir merged 1 commit intoRust-GPU:mainfrom
FractalFir merged 1 commit intoRust-GPU:mainfrom
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Currently, we replace unsupported
fptoui_satwithfptoui. This is incorrect(fptouiis wrapping, not saturating in CUDA) and UB-prone(casting values out of range is UB).fptoui_satcan be correctly emulated at the cost of 2 additional PTX instructions(max & min).This PR implements such emulation, removing another source of UB in Rust-CUDA.
(Equivalent, but slightly more complex approach can be applied to
fptosi_sat. I will implement that in a separate PR. After we fix that too, we can disable-Z saturating_float_casts=false, and remove that kind of UB fully.)