/tilegym-converting-cutile-triton-to-cutile-rs

IR Diff Checklist

When comparing original cudatile IR with cutile-rs generated IR, every item must be checked and resolved.

Pre-check: Correct kernel variant?

• Confirmed actual kernel name via nsys/torch.profiler (NOT assumed from source code)
• Confirmed launch config (grid, block) matches between dump and runtime
• Matched dump file to confirmed kernel name (CUDA_TILE_DUMP_TILEIR dumps ALL variants)

MUST match (correctness + performance critical)

• optimization_hints on entry — num_cta_in_cga, occupancy
• strides=[?,1] — last dim must be constant 1. For &Tensor params: auto. For raw ptr: use Array::<{[-1, 1]}> { dims: &[only_dynamic_val] }
• accumulator type — f32 for MMA, not f16
• ftof conversion — f32→f16 before store if accumulator is f32
• mmaf op types — input f16, accumulator f32
• token count — match original (usually 1 shared make_token)
• for loop step — matches original step size
• partition tile shapes — (BM x BK), (BK x BN), (BM x BN) match
• padding_value — neg_inf or zero where original has it (now supported since commit 4ba3a83)
• maxf/minf — should NOT have rounding_mode attribute (exact ops)
• grid size — persistent kernel grid must match (e.g., NUM_SM * occupancy)
• block size / num_warps — cutile-rs doesn't support simt_num_warps_in_cta, compiler chooses automatically

OK to differ (semantic equivalent)

• divi rounding<positive_inf> → (a + b - 1) / b — same semantics
• mini signed → if/else — same semantics
• get_index_space_shape → manual (dim + tile - 1) / tile — same semantics
• negative remi correction (xori+andi+select) → Rust % — may differ for negative values but blockId is always non-negative
• for ... step %assumed_var vs for ... step %raw_var — cutile-rs uses assume-wrapped variables

Expected noise (ignorable)

• Dead constant <i32: 1> / constant <i32: N> — from macro expansion, use --canonicalize to remove
• Extra assume bounded<0, ?> on blockId — auto-generated by cutile-rs
• Extra assume bounded<0, N> on for loop index — auto-generated
• Extra assume bounded<0, ?> on gridSize — auto-generated

Known gaps (cannot fix, record)

• make_strided_view — not supported in cutile-rs; use tview.partition(...) / tview.partition_mut(...) (lowers to make_partition_view in IR)
• tensor_dim_factor hint — may not appear in IR
• Debug info / source locations — cutile-rs doesn't generate
• simt_num_warps_in_cta — not supported as optimization hint