The loops the translator writes for narrow storage buffer stores and float atomic adds end only when their
compare-and-swap succeeds. With robust buffer access on, an atomic on a word outside its buffer may return anything,
so the compare can fail for ever and the GPU hangs until the device is lost, as reported right after the first
cutscene on an Intel Arc GPU (#610). New translator patch 0041 counts the attempts in a private word (a local cannot
count round a loop in that pass, which runs on SSA form) and leaves the loop after 4,096; contention on a word needs
about as many attempts as invocations race for it. Shared memory loops stay as they are: a shared word in range is
always settled, and the mesh programs run that loop for every primitive index byte.
Checked: all 4,238 NVN2 compute programs an installed shader cache stores translate and pass spirv-val (vulkan1.3); 45
contain a compare-and-swap, 11 of them in a storage loop, which grew by 256 bytes each and now compare the count with
4096; the other 34 are unchanged. tools/xlate_smoke.py passes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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