[arai713]

JIRA ID : AICK-2670

Motivation

The scalar lightning-indexer cases do not lower through the C++ engine, so the Python and C++ backends disagree for that body. test_attention_ir_cpp_parity.py::test_attention_ir_cpp_python_byte_identity fails when rocke_engine is built, with "rocke_engine.lower_serialized_ir: parse failed (status 1): operand '%c15' used before definition in op 'arith.select'". All six scalar-body harness cases (deepseek_hi64, glm_hi32, small on gfx942 and gfx950) fail at llvm20, llvm22 and llvm23. The four mfma_* cases are unaffected. CI missed it because the test skips when rocke_engine is not importable. This PR restores byte-identity for the scalar body.

Technical Details

• In _emit_scalar_body (library/kernels/common/lightning_indexer.py) the i32 zero constant was created after the key scf_for.
• IRBuilder.scf_for appends the loop op to the block immediately, so the constant landed after the loop that consumes it (the head-loop lower bound and the causal select).
• The Python lowerer folds constants to immediates and never noticed, but the C++ engine's parser enforces define-before-use and rejected the serialized IR.
• The fix moves the constant ahead of the scf_for so every operand is defined before the op that uses it, with a comment explaining the eager-append ordering constraint.
• Emitted LLVM IR is unchanged, so the goldens are untouched.

Test Plan

• test_attention_ir_cpp_parity.py with rocke_engine built and ROCKE_CPP_STRICT=1 at llvm20, llvm22 and llvm23
• test_dsa_indexer_golden.py at llvm20/22/23 to confirm the emitted IR is unchanged
• platform byte-identity gate (tools/check_byte_identity.py) across all families, to confirm no sibling define-before-use regression

Test Result

• Parity test was red before this change (define-before-use parse error) and is green after, at all three llvm flavors.
• test_dsa_indexer_golden.py passes at llvm20/22/23, confirming the IR did not change.
• Platform byte-identity gate is green across all 81 families plus the gfx1250 family at llvm23.

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/TheRock/blob/main/GOVERNANCE.md#pull-requests.

[therock-pr-bot]

✅ All Checks Passed — Ready for Review

Check	Status	Details
📝 PR Description	✅ Pass	—
⛔ Forbidden Files	✅ Pass	—
🧪 Unit Test	⚠️ Warning	Error: Source/code files changed without an accompanying unit test. Expected: add at least one test file named like test_<name>.py / test_<name>.cpp (or <name>_test.*). Current: code file(s) changed: dnn-providers/hip-kernel-provider/rocke/library/kernels/common/lightning_indexer.py; no test file found
🔎 pre-commit	✅ Pass	—
🚫 Draft PR	🔜 To Be Enabled	—
🚩 Feature Flag	🔜 To Be Enabled	—
📊 Code Coverage	🔜 To Be Enabled	—
🤖 therock-pr-bot	✅ Pass	—

🎉 All checks passed! This PR is ready for review.

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[therock-pr-bot]

🎉 All checks passed! This PR is ready for review.

[cgmillette]

Automated review: Model - qwen3.6:35b-a3b-coding-mtp-q4_K_M, effort: max

PR #14073 — emit indexer scalar-body zero const before its loop (arai713, AICK-2670) — 🟢 First-round: no closer look needed — verified fix for #14630

Prior item	Status
AnaghaRaoAMD (10-28): APPROVED at 916306eb	🟢 Current — given at head, the PR's only commit; no comments or threads (read)
Develop break (#14630, 10-29): parity gate red since #12548; engine rejects 6 scalar indexer kernels	🟢 FIXED 916306eb — a native engine built from each tree (develop d6957099 and the merge differ only in this file). Develop: test_attention_ir_cpp_python_byte_identity fails at llvm20/22/23/24 with operand '%c15' used before definition in op 'arith.select'; case by case 67/73 match, and the 6 failures are exactly the scalar indexer kernels. Merge: the file passes (2 passed, no skips) at all four flavors, 73/73 byte-identical. verify() is clean and parse(serialize(k)) round-trips for all 10 indexer cases; on develop the 6 scalar ones fail both (ran)
Bots / CI	🟢 Policy bot pass; its unit-test warning is moot, as the existing parity test is the regression test. At 916306eb every workflow passes (Multi-Arch CI and ASAN, Component CI, pre-commit, clang-tidy, hipDNN superbuild). hipkernelprovider passed on Linux gfx94X and Windows gfx110X (2 shards each), including rocke_golden_static and the indexer numerics on gfx942 hardware (5 scalar + 5 MFMA, Python-lowered; gfx950 skips without a GPU). No lane builds rocke_engine (14 "engine not importable" skips per shard) or runs the parity test, so CI cannot see this fix; #14630 proposes the CI change (read)
Our checks	🟢 Clean merge with develop d6957099 (17 behind) (ran). No re-bless: the indexer's Python-lowered LLVM matches develop for all 10 cases × 4 flavors, test_dsa_indexer_golden.py passes 8/8, the representative golden gate passes at all four flavors, and the differential goldens are OK (ran). Rule 9: all 312 harness cases (28 families) round-trip on the merge; an AST scan of the 282 x = b.scf_for / scf_for_iter / scf_if / scf_if_else(…) bindings (all four emit the op on creation) finds code emitted before the with only at this site on develop, and nowhere on the merge (ran). Rules 1–3 clean (ran)

#	Sev	file:line	Finding
N1	🟡	PR description	Nothing ties this PR to #14630: no Fixes keyword and no manual link, so there is no closing reference in either direction (read). Merging will not close the issue → add Fixes #14630 to the description. The rocKE merge monitor treats this PR as the fix either way

Utility: 🟢 Positive — one-line move restores C++/Python parity for six indexer kernels; LLVM unchanged.

---

Legend: 🔴 blocking · 🟠 should-fix · 🟡 minor nit · 🟢 info/good · ⚪ retracted

First-round review: a local qwen3.6 model made the independent first pass. The orchestrator (Claude Opus 5.5) verified it. On a clean merge with today's develop, and on develop alone, each with its own freshly built native engine, it ran the C++/Python parity test at llvm20/22/23/24 (as a whole and case by case), verify() on the indexer cases, the serialize/parse round trip over all 312 parity-harness cases, the indexer, representative and differential goldens, and an AST scan for the same bug shape. It also read the CI logs at head. The orchestrator owns this merge-worthiness call. It flags whether a closer look is needed; it is not an approval or a rejection.

[cgmillette]

LGTM, fixes develop

[assistant-librarian]

TheRock Submodule Bump Activity

Newest first

• 2026-10-30 — Included in TheRock via ROCm/TheRock#9594.