ser-coherence-hint-bits-overflow

Status: shipped (Phase 8) — see CHANGELOG.

What it detects

A MaybeReorderThread(hint, bits) call where bits > 16 (or the HitObject::MaybeReorderThread variant where the bits arg > 8). HLSL Specs proposal 0027 (SER, Accepted) caps the coherence-hint-bits arg.

Why it matters on a GPU

Values above the cap are silently truncated by the SER scheduler, producing incoherent reorder. The SER scheduler buckets lanes by the masked low hintBits bits of the hint argument; an overflow widens the input but the hardware ignores the high bits, defeating the developer's grouping intent.

Examples

Bad

MaybeReorderThread(hint, 24); // 24 > 16

Good

MaybeReorderThread(hint, 8);

Options

none

Fix availability

suggestion — Choose a bit count within spec.