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TOGSim C++ trace-generation pipeline (P0-P3): explicit dataflow producer + barriers#267

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TOGSim C++ trace-generation pipeline (P0-P3): explicit dataflow producer + barriers#267
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feature/togsim-cpp-trace

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@YWHyuk YWHyuk commented Jun 19, 2026

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What

Replaces the timing-path TOG producer (MLIR -> Python dict -> ONNX -> C++ TileGraphParser) with a compiled, shape-parametric trace producer: post-vcix MLIR -> skeleton -> EmitC -> C++ -> .so. TOGSim dlopens the .so, runs it to record an instruction trace, and feeds it into the existing Simulator/Core (timing core unchanged). Driven by a new --trace_so mode; the legacy ONNX-TOG path is kept and marked DEPRECATED, so nothing existing breaks.

Pipeline

post-vcix .mlir
  | build_skeleton.py        loops + memref.dma_start/wait -> togsim.* ; DCE the rest
  | dep_analysis.py          per-op read/write SRAM buffers (SSA) + vcix preload/matmul pairing
  | lower_to_emitc.py        togsim.* -> emitc.call_opaque ; drive upstream convert-*-to-emitc
  v
EmitC --mlir-translate--> C++ --g++ -shared--> trace.so
  | run_producer (dlopen)    EmitCtx callbacks record a TraceRec stream
  | togsim_trace_bridge.cc   TraceRec -> TileGraph (explicit dependency DAG)
  v
existing Simulator / Core    cycles, DRAM traffic

Dependency model (no in-order, no runtime tag-hash, no op heuristics)

Dependencies are derived from two sources available pre-collapse:

  • SRAM last-writer per buffer (load->compute, the Y_spad accumulator chain), recovered via SSA + a virtual SA_WEIGHTS buffer that folds preload->matmul.
  • The systolic array modeled as a pipeline (occupancy/latency split) with two explicit, distinctly-named barriers:
    • MEMORY_BAR (renamed from BAR): the DMA/tag memory fence; an async load -> compute waits the data's resp-complete.
    • COMPUTE_BAR (new): the compute fence; a store waits all systolic-array pipelines to drain.

Both barriers are first-class trace ops (togsim.compute_barrier -> ABI togsim_compute_barrier) visible in the trace dump and the instruction stream.

Status

  • 256^3 GEMM runs end-to-end through the real Simulator via --trace_so.
  • Cycle comparison vs the legacy build_tog path on the same kernel + gem5 cycle_list: compute work and DRAM traffic match; matmuls pipeline on 2 SAs; the memory fence correctly delays compute until the weight load arrives.
  • Known open items (documented in docs/design/togsim_cpp_trace.md sec 10): preload-concurrency cap (needs non-zero preload occupancy), parallel output tiles (dispatch granularity), broader op coverage (conv/SDPA/vector).

Testing

  • tests/test_togsim_skeleton.py, test_togsim_emitc.py, test_togsim_runtime.py (7 tests).
  • Manual --trace_so GEMM through TOGSim.
  • Legacy path untouched (comment-only DEPRECATED markers).

Design of record: docs/design/togsim_cpp_trace.md (sec 9-10).

🤖 Generated with Claude Code

@YWHyuk YWHyuk force-pushed the feature/togsim-cpp-trace branch 3 times, most recently from 1151f6a to 7f70bbb Compare June 22, 2026 12:13
@YWHyuk YWHyuk force-pushed the feature/togsim-cpp-trace branch 5 times, most recently from c166abd to ed5c747 Compare June 25, 2026 07:29
YWHyuk added 21 commits July 7, 2026 16:09
… feed

Skeleton + EmitC + cost/dep analysis on the frontend; the trace runtime,
loader, bridge, and Core feed on the simulator; shared MLIR pass helpers and
the pipeline tests.
Per-record tag key in the bridge plus per-iteration tag alloc in
dma-fine-grained so multi-tile-K and conv loads do not collide; strip the
reduction accum marker from the memory_barrier slot.
togsim_dispatch with TILE_BEGIN/TILE_END; outline each work-item into
togsim_kernel_tile.
DMA-capacity throttle and frozen-state guard, per-core VMEM in the configs,
and the SA weight-buffer throttle.
trace_timeline.py with per-work-item grouping and resource-centric DMA lanes;
the trace logs the first DRAM response and the assigned systolic array, and
scopes the compute barrier to its dispatch.
Default to the trace path; fix uninitialized Instruction fields, the matmul
accumulator wedge, fused-subtile dedup, nested/fused epilogue dataflow, and
dma_wait fusion; bound concurrent dispatches to the spad, round-robin
work-items within a partition, benchmark autotune and run the multi-tenant
scheduler through the trace path, and emit trace.so for pooling/reduction.
Carry simulator headers through the wrapper for cache-safe replay; drop verbose
[P3-trace] logs; fix the key.mlir compile race in load().
… runtime model

Replace the trace bridge's accumulated special cases with one dataflow rule and
clean up the runtime that consumes it.

Dependency rule: per SRAM buffer keep a writers SET; a reader depends on all
current writers (occupancy=ISSUE when both are systolic-array ops, else
latency=DONE); a writer REPLACEs the set. The only exception is is_mm_accum (a
matmul that reads and writes the same buffer = a commutative accumulator): skip
its read edge and UNION its write, waiting only the non-matmul init seed and not
ordering co-matmuls. This drops the matmul-accumulator chain that deadlocked the
SA weight-slot pipeline while keeping the init->matmul edge, and lets a vector
epilogue or the store wait every K matmul (fixes the pure-vector store that an
empty COMPUTE_BAR let slip).

Remove COMPUTE_BAR entirely: a matmul is its own DONE-handle (finish == SA
drain), so the store JOINs the matmul writers directly. The whole emit/loader
chain is gone -- build_skeleton, lower_to_emitc, togsim.compute_barrier, the
runtime symbol, the Opcode/case/_fence_finish, and TraceRec::COMPUTE_BAR -- so a
stale producer fails loudly instead of emitting records the bridge would drop.
Only MEMORY_BAR remains (an async load's DONE is its data arrival, not issue).

Model compute-output spad footprint in the SRAM version/capacity machinery so
buffer reuse (WAR) is capacity-modeled, not a hard edge. The output size comes
from the DMA records that touch the same buffer (a buf_bytes pre-pass); an
in-place buffer (accumulator, relu) is version-transparent so footprint is not
double-counted. The occupy gate and version release sit in the MOVIN/MOVOUT/COMP
issue points (release before the COMP skip path so a skipped matmul still frees).

Runtime: collapse child_inst / _pipeline_children into one event-indexed
_deps[ISSUE|DONE] with add_dep(c, on) and fire(e); collapse the weight-slot
release queue and the async-load wakeup into one _due_events timed-effect table
drained by process_due_events. Both are behavior-preserving (byte-identical).

Require the weight-slot model: sa_weight_buffer_depth must be > 0 (errors at
init), and the round-robin disable mode is removed. Degenerate traces (a
consumer-less preload, an unpinned matmul) hit explicit error+exit guards rather
than asserts that vanish under NDEBUG.

Mark the legacy ONNX TOG path deprecated: it is superseded by the trace path, so
TileGraphParser logs a deprecation warning and the TORCHSIM_LEGACY_TOG=1 opt-in
warns at command build.
… spad/2

The validation-binary spad-overflow check sat inside `if functional_mode:`, so in
timing-only / autotune (non-functional) runs an over-spad tiling was never
rejected and reached TOGSim, which wedged ("spad too small") and crashed the
compile via assert 0. Move the compile + check out of the functional gate (the
Spike execution itself stays gated, run_spike below) and budget per dispatch at
spad/2 -- two work-items run concurrently (double buffer), so each must fit half
the spad or they deadlock competing for it. This matches the GEMM tiling gate
(max_spad_size = spad/2), which pointwise ops lacked. Fixes the resnet /
test_scheduler wedge where a fused BatchNorm+ReLU tile exceeded spad/2.
Every generated trace.cpp now opens with a "GENERATED ... DO NOT EDIT" banner
carrying the TOGSim ABI version and the togsim_* call formats, so a dumped trace
is self-documenting. Both are read from togsim_runtime.h at codegen time -- the
version from the TOGSIM_ABI_VERSION define, the call-format text from a marked
block next to the declarations -- so they never drift when the ABI changes.
…rint

The bridge sums each work-item's distinct-buffer footprint (each buffer once, so
a reduction's reloads of the same section do not inflate it) onto its Tile.
can_issue then admits two concurrent dispatches only when each fits half the
spad; a dispatch larger than spad/2 runs alone with the whole spad, so two
work-items never compete for the shared spad and deadlock -- a runtime safety net
beneath the codegen spad/2 gate. The footprint and resulting max_dispatch are
logged on the TILE_SCHEDULED trace line for debugging.
…election

select_tile fed the epilogue buffer count to gemm_combination_mapping as
max(n_extra_read - 2, 0), which optimistically assumed the X and W DMA buffers
were already freed and reusable by the epilogue. The codegen lays every buffer
out as a disjoint .spad global and never reuses freed space, so the estimate
undercounted the real footprint: for a fused matmul+relu kernel the budget came
to 64512 B/lane (treated as a bare GEMM) while the emitted kernel used 89088
B/lane including the relu output buffer. Under the full-spad guard this was
harmless (89088 < 131072), but the spad/2 guard rejected it and crashed
test_transformer_fusion with SpadOverflowError, since the heuristic path has no
tile-shrink fallback.

Pass n_extra_node + n_extra_read instead: one output-tile-sized buffer per
epilogue node plus one per extra read operand, matching what the codegen emits.
For the matmul+relu kernel the budget now equals the actual footprint exactly,
and tile selection picks TILE_M=128 (62976 B/lane) which fits spad/2.

Liveness-based spad reuse and broadcast over-allocation are tracked separately
as optimizations in issue #275.
The spad-overflow check summed the kernel stack frame into the per-lane
scratchpad usage (spad_usage = stack_size + spad_size) and rejected the
tiling when that exceeded the spad/2 budget. But only the .spad section
actually lives in the scratchpad -- it is pinned there by the
--section-start=.spad link option. The kernel stack is in main memory
(sp is set up by pk in the -m region, not at the scratchpad vaddr), so it
does not consume the scratchpad and must not be charged against it. The
scalar frame is also shared across lanes, not per-lane, so adding it
double-counted.

On small configs (8x8) this falsely rejected feasible tilings: the
wrapper3 conv2d/resnet/mistral kernels fit the 32 KB spad with room to
spare but were tripped over the spad/2 gate purely by the ~200-800 B
stack term, crashing compile with SpadOverflowError. Drop the stack
term; the .spad-only check still correctly rejects real buffer overflows
(e.g. sparsity, which is fixed separately by f05ac8a).
Spike v1.0.3 zero-inits the MVIN/MVOUT DMA address buffer so ROUNDUP
padding entries are skipped instead of dereferencing uninitialized
garbage, fixing the host store segfault on 8-lane (wrapper3) configs
where a tile's split axis is not a multiple of vlane_stride*n_vu.
Add pytorchsim_functional_verify_per_kernel, a sub-option of
pytorchsim_functional_mode that localizes the first compiled kernel whose Spike
output diverges from a CPU reference.

When enabled, the generated wrapper compares every realized buffer (the output of
each fused kernel) against a CPU "golden" computed once per call by running the
original aten graph (V.graph.module) on CPU with the same inputs, via an
fx.Interpreter that records each node's output by name. A buffer is mapped to its
originating fx node through V.graph.get_buffer().origin_node, so the check reports
the kernel, the originating op, the offending indices and the max abs diff, then
raises at the first divergence (stop-at-first). Comparison granularity is the
fused-cluster output, the finest observable in a fused pipeline.

Auto-disabled when functional mode is off (no Spike values to verify); the config
accessor AND-gates the key with functional mode. Codegen bakes the
verify_init/verify_check calls into the wrapper only when enabled at compile time,
so clear the codegen cache when toggling. Tolerances via
TORCHSIM_FUNCTIONAL_VERIFY_RTOL / _ATOL (default 1e-4).

extension_functional_verify.py holds the graph registry and the runtime
golden/compare logic; mlir_codegen_backend injects the calls at the wrapper level;
extension_config reads the new YAML key.
The BMM tile selector fed only n_extra_node to gemm_combination_mapping and
dropped the prologue's extra-read operands entirely, so a softmax-fused
attention matmul (value^T @ softmax(scores)) was tiled as a bare BMM. The
codegen lays the softmax max/sum operands out as their own disjoint
weight-tile-sized .spad globals (buf3/buf4) and never reuses freed space, so
the estimate undercounted the real footprint: on the 32x32 wrapper2 config
(16 KB/lane spad/2 budget) tile selection picked TILE_N=512, whose emitted
kernel used 16896 B/lane and overflowed the budget by 512 B, crashing
test_transformer with SpadOverflowError. Under the 128x128 full-budget config
the slack hid it. This mirrors the epilogue n_extra_read gap fixed for the
GEMM template (commit f05ac8a), now on the BMM prologue path.

Add an n_prologue_extra_read knob to gemm_combination_mapping that charges
each extra prologue-read operand as one weight-tile-sized (TILE_K x TILE_N)
.spad buffer, matching what the codegen emits, and have the BMM template count
those operands the same way codegen does (the one numel-matching main input
reuses the matmul-operand buffer; every other read gets its own global). Tile
selection now rejects TILE_N=512 (16896 B/lane) and picks a fitting tile
(8704 B/lane), so wrapper2 test_transformer passes the full Spike + allclose
check. The new parameter defaults to 0, leaving the GEMM and conv callers
unchanged.
Add docs/per-kernel-functional-verify.md (usage, options, mechanism,
limitations, code map) and point to it from CLAUDE.md: a one-line entry in the
debugging section and in the YAML knobs list.
Keep only a one-line note on what TOGSIM_ABI_VERSION guards; the per-bump
v1..v12 history was noise nobody reads.
YWHyuk added 4 commits July 7, 2026 16:09
A fused template epilogue (matmul/conv + relu/add/gelu/...) stores its result via
store_epilogue, which -- unlike the plain store() -- emitted no masked-DMA clamp. On
a non-dividing output the store then wrote the systolic pad region past the real
extent, corrupting the result (fused matmul+relu at 10x10x10 was off by ~7).

store_epilogue now clamps each output tile dim to [0, extent): the extent of every
loop iv is ranges[k], and the tile dims are indexed by dim_aliasing (tile-dim order),
so a dim whose iv extent does not divide the tile is clamped. Keyed by iv name, it is
naming-agnostic -- it covers both the index-N matmul epilogue and the c0/tile_n/...
conv epilogue -- and _emit_clamp skips dividing dims, so a dividing output is a no-op.

Fixes fused matmul/conv epilogues on non-dividing shapes (matmul+relu/add/gelu,
conv+relu/scale/bias/sigmoid, non-dividing K and non-dividing output). No regression:
test_matmul, matmul_activation, addmm_residual, matmul_scalar all pass.
Hand-write a masked MVOUT togsim.transfer, run lower_transfer_to_gemmini in-process
(no torch, no spike; skipped without the MLIR bindings), and compare to an embedded
golden -- the exact lowered IR (MLIR SSA numbering is deterministic for a fixed
input): the i32-view descriptor global (dim_size / config_type / masked flag
packed), the runtime dim_low/dim_high stores at i32 idx 6/10 for masked_axes=[2],
and the CONFIG_DESC + MVOUT asm. A second case adds subtile_size=[1,1,4,8] and shows
the descriptor dim_size become the subtile (config) shape. Timing mode erases the
transfer. Under tests/lowering/ so further per-pass goldens have a home. Regenerate
the golden and review the diff on an intended lowering change.
…dims, cleanup

Addresses the PR review of the masked-DMA non-dividing work:

- _masked_fill_bits detected a log-sum-exp reduction with `"exp" in origin.name`, which
  also matches expand / expm1 / experimental -- an ordinary non-dividing sum whose origin
  name contains "exp" would then get a -inf tail fill instead of the sum identity 0 and
  reduce to -inf. Match the op target instead (_origin_is_exp: the target's overload
  packet name == "exp"); same fix applied to the get_padding_type twin. Unit test in
  tests/lowering/test_masked_fill.py pins that expand/expm1 do not match.
- Remove the self._last_local_dims temporal coupling: get_dma_info now returns local_dims
  and load()/store() pass it to _masked_bounds explicitly, so a reordered or skipped
  get_dma_info can no longer feed stale clamp axes.
- Drop the underscore-prefixed locals in def_dma_op / store_epilogue (non-idiomatic),
  trim the oversized _masked_fill_bits / _masked_bounds docstrings to the invariant plus a
  link to docs/design/masked-dma-descriptor.md, and clarify the bf16 dtype-table comment
  (present only for table totality; bf16 is not actually supported).
Dropping the tile-divisibility recompile means non-dividing shapes rely entirely on the
masked-DMA clamp/fill; a gap is now a silent wrong answer, not a slow-but-safe recompile.
Add tests/ops/misc/test_masked_nondividing.py pinning that path: 2-D constant pad (per-dim
greedy pad recovery), sum over a broadcast operand (0 fill, guards the exp-substring bug),
softmax (genuine -inf fill), non-dividing elementwise, and non-dividing gather. Register it
in the CI allowlist (pytorchsim_test.yml). Also add the missing trailing newline to
test_indirect_access.py.
@YWHyuk YWHyuk force-pushed the feature/togsim-cpp-trace branch from 1e43e9a to cfcb7a9 Compare July 7, 2026 07:10
YWHyuk added 2 commits July 7, 2026 19:45
…ilogue

The ordered-steps refactor removed the reduction masking mechanism (self.masks /
get_mask / mask_cse) but left a compute_body.splice(self.masks) in
codegen_epilogue_body, so any matmul/bmm + reduction fusion crashed with
AttributeError: no attribute 'masks'. It was masked until now by the stale-spike
illegal-instruction CI failure. Remove the dead splice; test_matmul_reduction
(matmul+max, var_mean, residual+var_mean) passes. Non-dividing reduction-fusion
masking (padded lanes vs the reduction identity) stays a separate gap from that
refactor.
…ixel_shuffle trace)

Both the Gemmini descriptor and the TOGSim DMA model cap at 4 tile dims, but a
logical tile can exceed 4D (e.g. pixel_shuffle splits two spatial axes -> a 5D
tile [1,1,2,4,2]). lower_transfer_to_gemmini reduces >4D as part of emitting
Gemmini asm, but that runs only on the Spike/gem5 lowering path. The trace
producer (build_tog) reads togsim.transfer BEFORE that, so it emitted a 5D DMA
and TOGSim rejected it: "issued tile is not supported format.. tile.size: 5".
Exposed by the pixel_shuffle case newly added to the wrapper1 CI suite.

Add a peel_transfer POST_OPT pass that reduces every >4D togsim.transfer up front
(before build_tog) while KEEPING it a togsim.transfer, so both consumers see <=4D.
It mirrors lower_transfer_to_gemmini's two reductions: collapse unit dims when the
effective rank is <=4 (memref.collapse_shape), else peel the outer effective dims
into an affine.for nest with the lane-banked physical SRAM offset. The gemmini
lowering keeps its own reduction as a now-defensive no-op.

Validated on 128x128: test_floormod_axis_split (pixel_shuffle + 9 others),
test_masked_nondividing, test_matmul, test_conv2d all pass.
@YWHyuk YWHyuk force-pushed the feature/togsim-cpp-trace branch from f280164 to 1e2a3a9 Compare July 7, 2026 11:12
YWHyuk added 8 commits July 7, 2026 20:36
…-safe)

_GoldenInterpreter recorded each node output on CPU but returned the original
(npu) tensor to downstream nodes, and cast the recorded value to float32. A
device-baked op (e.g. arange on npu) or a consumer that requires operand device
agreement (aten.index needs its index tensors on the indexed tensor's device)
then saw a mixed CPU/npu pair and the whole golden threw, silently disabling the
per-kernel verify for that graph -- e.g. MobileNet's depthwise conv lowered to
constant_pad + index gather.

run_node now moves EVERY tensor output to CPU (preserving dtype) and returns it,
so downstream nodes see CPU operands; only the recorded golden is cast to float32
for the allclose compare, so int index tensors stay usable.
The cat template's _calculate_input_tile_sizes handed each input a
concat-dim tile of min(extent, remaining_spad_budget). When that budget
did not cover an input's full concat extent, the tile width could fail
to divide the extent (e.g. extent 64, tile 62 on the 8-lane config).
The copy loop steps by that tile over [0, extent), so a non-dividing
tile produces a ragged final iteration with no remainder mask: the MVIN
over-reads past the input and the MVOUT over-writes past the output,
corrupting the result.

This surfaced on the 8x8 (wrapper3) CI config, where the per-input spad
budget lands at 126 for two 64-wide inputs, truncating the second tile
to 62. It scrambled ~45% of the cat output and broke LlamaDecoderLayer
(rotary rotate_half cat) and the diffusion UNet skip-connection concat.
Larger arrays give a bigger budget so both inputs got the full 64-wide
(dividing) tile, which is why 32x32 and 128x128 passed.

Snap each input's concat-dim tile down to the largest divisor of its
extent that fits the budget, so every loop iteration is full-width and
in-bounds. When the budget already covers the full extent the tile is
unchanged, so 32x32/128x128 codegen is a no-op.

Verified with a minimal cat repro (64+64 -> 128 on 8x8: fails before,
diff 0 after) and the real test_llama LlamaDecoderLayer at 8x8 (now
passes).
The vlane index_expr lowering reconstructs each lane element's logical
index along the split axis as stride_dim + outer_dim * nr_vector_lane,
where outer_dim is the sublane-row index. The next sublane row starts
vector_lane * vlane_stride elements later (vector_lane lanes, each
holding vlane_stride positions), but the multiplier used nr_vector_lane
alone, dropping the vlane_stride factor. Any index tensor (e.g.
arange/iota) whose split axis spills into a second sublane row then had
every row past the first come out shifted, producing wrong values.

This fired on the 8x8 (wrapper3) config: arange(32) at 8 lanes with
vlane_stride 2 needs two sublane rows, so positions 16-31 came out as
p-8. Larger arrays keep the 32-wide axis in a single row (outer_dim
always 0), which is why 32x32/128x128 were unaffected. It broke
test_llama's LlamaModel (rotary position ids) at 8x8.

Multiply the outer/row term by vector_lane * vlane_stride. This equals
the old value whenever vlane_stride == 1, so single-row splits and
larger configs are a codegen no-op.

Verified with a minimal arange(32) repro at 8x8 (positions 16-31 wrong
before, diff 0 after) and the full test_llama LlamaModel at 8x8 (now
passes).
init_tile_size gave a 1-D tile of 2*vlane_stride*vector_lane regardless
of the data extent. When the extent is smaller than that tile the
reduction/pointwise MVIN reads past the end of the DRAM buffer, and the
compute loop folds the out-of-range elements into the result. For a sum
reduction that means adjacent-DRAM garbage is squared/added into the
sum.

This broke test_single_perceptron's Loss on the 128x128 config: the MSE
mean reduces 128 elements but the tile was 2*2*128 = 512, so the MVIN
over-read 384 elements past the 128-wide input and roughly doubled the
squared-error sum (loss diff ~4593). It fired on wide-lane configs
(tile 512 > extent 128); 32x32 gives tile 128 == extent and 8x8 gives a
tile that divides 128, so both were unaffected.

Cap the 1-D tile to min(2*vlane_stride*vector_lane, extent) so the tile
never exceeds the data. It is a no-op whenever extent >= tile, so larger
reductions and other configs are unchanged.

Verified with a minimal mse_loss(1-D) repro at 128x128 (over-reads
before -> diff 0 after, across extents 64/100/127/200/300) and the real
test_single_perceptron at 128x128 (Loss now passes).
torch.sort's frontend lowering exposes the sorted VALUES as the sole
scheduler-visible template output; the INDICES buffer is written in place
by the same kernel (make_inplace) but is not registered as an output. For
argsort the values output is dead, so Inductor DCEs the whole sort kernel
and the indices buffer is returned uninitialized (all-zeros), silently
corrupting any argsort result (e.g. DeepSeek MoE expert routing).

Register the in-place indices write as a MutationOutput owned by the sort
operation so the scheduler keeps the kernel alive whenever indices is
consumed. OperationBuffer.get_outputs() hardcodes [self], so add a small
MLIRTemplateBuffer subclass that can own extra MutationOutputs and have
MLIRTemplateCaller.output_node build it; the sort lowering attaches the
indices mutation via add_mutation_output. For templates with no mutation
this is behaviorally identical to the base (get_outputs == [self]).

Then gate the values MVOUT on the values output being live: in argsort it
is pruned from the kernel args, so emitting its MVOUT referenced an
undeclared %YV. The values scratchpad is still produced internally for the
bitonic compare; only the dead DRAM store is skipped.

Verified: t.argsort() now returns correct indices (was all-zeros); torch.sort
with both outputs live is unchanged; test_sort, test_matmul, test_cat,
test_indirect_access unaffected by the output_node change. Note: x[argsort]
end to end additionally needs the indirect-gather codegen fix (separate).
convert_indirect_indexing moves an indirect index into an offset spad and
zeros the indirect term in the DRAM base-offset expression, but it only
walked index.args. A BARE indirect index (x[idx], where the load index IS
the symbol so index.args is empty) was left unzeroed, so the DMA base
offset's affine.apply referenced the loop-local index SSA value before it
was defined ("use of undeclared SSA value name"). Any 1-D gather with a
runtime index tensor failed to compile at codegen; it was masked for
argsort only because the sort DCE bug left the indices all-zero (a
degenerate constant load).

Subs any remaining indirect symbol to 0 after the arg loop (mirrors the
store path). The per-position gather is carried by the offset spad, so the
base offset is correctly 0.

Verified: x[idx] (N=32/64) and x[x.argsort()] now compile and match CPU;
test_indirect_access.py (incl. scatter/index_add and multi-dim) and
test_sort.py unchanged.
_masked_bounds reverse-engineered per-dim padding from the single flat
index offset and clamped each padded load to [pad, pad + input_extent).
That recovery is ill-posed: the offset mixes the tap shift with the
padding, and under channels_last the stride-1 channel axis absorbs the
offset remainder, producing an impossible clamp (e.g. [4, 8) on a size-2
channel tile). Spike then zeroed the whole load, making channels_last
depthwise conv 99.9 percent wrong while NCHW was fine.

The clamp was also unnecessary: at pad positions the consumer already
yields the correct value (a compute-side select for a padded gather, or
the pad op's own fill), so reading OOB is harmless. Keep only the ragged
tail clamp (glo=0, ghi=loop_extent), which is genuinely load-bearing for
non-dividing tiles.

Verified on 32x32: channels_last depthwise conv now matches CPU; NCHW
conv and standalone ragged F.pad still pass. Broader regressions (padded
reduction loads, full MobileNet) to be addressed separately.
codegen_epilogue_body() decided whether to emit the template buffer's MVOUT
by asking "did a fused epilogue already store something?":

    if len(self.stores._lines) == 0:
        template_store()

That is a proxy for the real question, "does anything outside this kernel still
read the template buffer?", and it is wrong in two of the four cases:

  - epilogue + live template buffer  -> store skipped, buffer never written
  - no epilogue + dead template buffer -> store emitted for a pruned DRAM arg

The first case corrupts DeepSeek-V3's MoE gate. The gate is
sigmoid(mm(hidden, gate_w) + bias), so add+sigmoid fuse onto the GEMM template,
but the raw mm result is also read by a later gather kernel. Its buffer was
declared as a kernel output and never stored, so the gather read an
uninitialized buffer (all zeros), scrambling expert routing. Every config was
affected; only 8x8 crossed the test's loose atol=2e-1 (final Max abs diff
0.2546) while 32x32 landed just under it and passed.

Ask the real question instead. Inductor already answers it:
Kernel.remove_kernel_local_buffers() drops a buffer only when
Scheduler.can_buffer_be_removed_through_fusion() finds every user inside this
fused kernel. A buffer that survived removal therefore has an outside user and
must be stored. Record the template buffer's name in def_kernel() and
def_conv_kernel() (conv has its own implementation) and gate template_store()
on it, in both the main and the reduction_fusion branches. The proxy is gone.

Use the kernel-local self.removed_buffers, not V.graph.removed_buffers: the
former is what remove_buffer() populates, and the latter is still empty when
the store hook runs.

Note this makes a previously missing MVOUT issue, so DRAM traffic and cycle
counts rise for any model with a live template buffer under a fused epilogue.
That is the correct cost, not a regression, but reported cycles will shift.

Verified on the 8x8 config: test_deepseek_v3_base goes from Max abs diff 0.2546
to passing; a dead template buffer (relu(mm)) still prunes its DRAM arg and
emits a single MVOUT; the trace/TOGSim timing path runs with the extra store.
Regressions pass: test_bmm_reduction, test_matmul, test_bmm, test_conv2d,
test_cnn, test_group_conv, test_pool, test_reduce, test_softmax, test_layernorm,
test_mlp.
@YWHyuk YWHyuk force-pushed the feature/togsim-cpp-trace branch from 3fd7ae1 to 79b1aec Compare July 9, 2026 05:00
Jagggged and others added 12 commits July 9, 2026 15:28
Implement abs, sign, isnan, isinf, fmod, bitwise shifts, copysign, erfc,
hypot, cosh, sinh, acos, asin, atan, atan2, acosh, asinh, atanh, and log/
atan (VCIX) in the Inductor MLIR backend. Float-only transcendentals cast
non-float inputs to f32 while leaving native float widths (f16/f64)
untouched.
Port the C++ MathLog/MathAtanToVCIX patterns to the in-process Python
VCIX pass: add math.log (opcode 2, imm 2) and math.atan (opcode 2, imm 3)
to _MATH_VIV and MARKERS. Encoding matches the spike rs1 / gem5 VS1
sub-opcodes (sin=0, cos=1, log=2, atan=3). No C++ mlir-opt pass needed.

gem5 decodes vlog_v/vatan_v into the CustomVlog/CustomVatan op classes,
so give them a functional unit as well. Without one the Minor CPU warns
"No functional unit for OpClass CustomVlog" and gem5 exits 1 on any
kernel containing torch.log or torch.atan. They belong in
SpecialFunctionUnit (opLat 10) next to exp/erf/tanh/sin/cos rather than
in a 1-cycle unit, since they are transcendental.

Co-Authored-By: Claude Opus 4.8 <[email protected]>
Claude-Session: https://claude.ai/code/session_01MTjfq7HAexdCKopgp42rKE
Add the pointwise op test under tests/ops/elementwise and register it in
the test workflow allowlist.
Bump the third-party pins to the releases shipping the new pointwise
instructions (spike torchsim_vlog/vatan, gem5 CustomVlog/Vatan + decode).
reduction_init returned "-inf"/"inf" for max/min regardless of dtype, so an
integer max/min reduction fed an invalid inf identity into every consumer:
the accumulator init, the template reduction init, and the masked-DMA tail
fill (torch.tensor(inf, dtype=int64) overflowed -- surfaced compiling swinv2
with batch>1). reduction_combine_vec also hardcoded the float multi_reduction
kinds <maximumf>/<minimumf>, which reject integer vectors.

Return the dtype's representable extreme from reduction_init for integer
max/min (max identity -inf -> iinfo.min, min identity +inf -> iinfo.max;
bool -> 0/1), and emit the signed-integer multi_reduction kinds <maxsi>/<minsi>
for integer element types. sum/prod need no change: the <add>/<mul> combining
kinds are polymorphic and ops.add/ops.mul already select arith.add{i,f} by
dtype (as ops.maximum/minimum already select maxsi vs maximumf).

Verified: int amax/amin/sum/prod reductions compile and match CPU; float
test_reduce (ReduceMax) and test_softmax unchanged. Also clears the swinv2
batch>1 masked-fill overflow (it then hits a separate unsupported
shifted-window view, tracked separately).
…lar DMA index

torch.roll has no Inductor lowering; it decomposes to index_select(fmod(...)) -- a
cyclic-shift gather whose ModularIndexing DMA index the affine-only descriptor
cannot express ("Unlinearized floor/mod in DMA index"). Rewrite it as the two
contiguous halves the shift produces, stitched by cat:

    roll(x, s, d) == cat([slice(x, N-s, N), slice(x, 0, N-s)], d)

each half is a plain strided slice with no modulo. Do it as a lowering (removing
roll from the decomp table so it is not decomposed first) rather than a
decomposition, so we can also REALIZE the input with copy_input: roll's producer
is often a reshaped view (e.g. swinv2's window_reverse), and the slice offset would
otherwise fuse into that reshape's modular index, re-creating a shifted (p+c)%m
form. A plain .contiguous()/clone does NOT create the buffer boundary (Inductor
inlines it); copy_input does.

Verified: torch.roll (1-D / multi-dim / arbitrary shift) and roll+reduction match
CPU; swinv2 batch>1 now compiles through the shifted-window attention (previously
blocked by the roll's cyclic shift and then by the fused slice offset).
A composition of aligned reshapes on one iteration variable (e.g. swinv2's window
partition fused with a later reshape) leaves a nested index like
ModularIndexing(ModularIndexing(p, 1, 64), 1, 8) that neither sympy nor
simplify_with_ranges reduces. collect_boundaries then skips its cut points (the
inner base is not a bare variable) and the affine-only DMA check rejects it.

Add a general, pattern-free canonicalizer (flatten_nested_floormod / _as_digit):
any nesting of FloorDiv/ModularIndexing over a single symbol is a digit extractor
(v // A) % M and collapses to one level by composing divisors, from four
divisibility-guarded algebraic identities. Applied in collect_boundaries and in
_fold_with_ranges. Multi-variable inner arguments (e.g. a roll shift v+c) are left
untouched.

Verified: numeric equivalence on the swinv2 window index; test_reduce, test_layernorm,
test_cat, test_indirect_access unaffected.
The wrapper header imported empty_strided but not empty_strided_cpu, so a graph
that allocates a CPU-side buffer (e.g. swinv2's shifted-window attention mask,
which Inductor keeps on CPU) failed at runtime with
"NameError: name 'empty_strided_cpu' is not defined". Add the same binding the
default Inductor PythonWrapperCodegen header provides.
…yout

A per-lane reduction is lowered as a 2-D [reduction | batch] collapse:
multi_reduction reshapes the accumulator to <reduction_numel x red_size>
and reduces axis 0, which assumes the reduction axis is the outermost
in-lane run and every non-reduction (batch) axis is inner. get_dma_info
reorders the tile axes for reduction loads to guarantee that, but only
for the 2-D and 3-D cases. The 4-D case mis-tested is_reduction
(reduction_depth < 3, false once there are three batch dims) and then
raised NotImplementedError, and rank 5+ fell through to the default
row-major order -- both leaving the reduction axis innermost, so the
reduce collapsed a batch axis instead of the reduction axis.

This is hit whenever a non-reduction dim-merge is blocked and an extra
batch axis stays in-lane: SwinV2 cosine window attention adds a gathered
relative-position bias (table[idx[q,k], head]) before the softmax amax,
keeping head separate from query (4-D tile, head bled into the max), and
its post-attention LayerNorm var_mean splits the token axis into several
loop vars (6-D tile, mean off by ~0.005).

Generalize the reorder to any tile rank: a tile that carries the
reduction axis places that axis-group outermost via
range(r, L) + range(r-1, -1, -1), which reduces to the existing 3-D
order for L=3. Adds test_reduce_gather_bias (fails max abs diff ~3.3
before the fix).
SwinV2 batch>1 used to fail codegen with "Unlinearized floor/mod in DMA
index" because the shifted-window path (torch.roll composed with window
partition/reverse) produced views axis-split could not linearize. With
the roll->slice+cat lowering, the nested/shifted mod handling, and the
reduction-axis layout fix, the whole backbone now compiles and matches
CPU end to end (max diff ~5e-6 for image 64 / window 8 / batch 2).

Add tests/models/test_swinv2.py, wire it as a self-hosted CI job next to
the other model tests, and list SwinV2 in the README model coverage.
conv_multi_tile_mapping (used for batch > 1 convs) collects every tile
that fits SPAD into tile_candidates and returns them sorted, but it
guarded the "no mapping" error on max_used_spad_size instead of on
tile_candidates. max_used_spad_size is only bumped when a candidate also
satisfies max_k_h_w <= k_h, and max_k_h_w is initialized to K_W, so it
only ever fires for the full-kernel (k_h == K_H) tile. When that tile
overflows SPAD -- e.g. a CLIP ViT-B/32 patch conv (3->768, 32x32 stride
32) at batch > 1 -- the guard raised "Cannot find a valid mapping" even
though smaller-k_h tiles fit and were already in tile_candidates. The
mapping variable it tracks is never returned.

Guard on `not tile_candidates` instead, so the conv is rejected only
when no tile fits at all. The returned candidate list is unchanged, so
convs that already worked are unaffected. Adds a batched patch-conv case
to test_conv2d.py. Fixes issue #252.
With the conv-mapping fix, CLIP's vision transformer runs with batch > 1
and matches CPU end to end (max diff ~1e-5). Add tests/models/test_clip.py
(CLIPVisionModel, batch 2, patch 32), wire it as a self-hosted CI job,
and list CLIP in the README model coverage.
@YWHyuk YWHyuk force-pushed the feature/togsim-cpp-trace branch from ae26ede to 2463f82 Compare July 10, 2026 05:11
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