Apple Target IR fusion descriptors — emit + consume (Decision #19) - #63
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… slice 1) The Apple Target IR fusion passes re-discover the matmul→softmax[→matmul] / matmul→gelu / ... chains the canonical compile already recognized (COMPILER_AUDIT "fusion intent is too late"). This lands the flagship slice that makes the fusion decision first-class in Target IR. MatmulSoftmaxMatmulFusionToAppleGPU.cpp now: - EMITS the descriptor on the fused call — tessera.fusion.kernel = "matmul_softmax_matmul" + tessera.fusion.source = "descriptor" | "rediscovered" — so the fusion decision (which kernel, and whether the compiler's intent drove it vs. structural re-discovery) is auditable in the IR (Decision #19). - CONSUMES an upstream tessera.fusion.intent on the tail op: when present the fusion is descriptor-driven (source="descriptor"); absent it, the structural walk re-discovers it (source="rediscovered", back-compat). Both fuse to the same kernel. - On a descriptor/IR disagreement (intent set but structure doesn't match) emits a Decision-#21 warning naming the op instead of silently falling back. Built clean; full tessera-ir lit 119 pass / 0 fail (existing fusion fixtures unaffected by the new call attrs). Tests: tests/tessera-ir/phase8/apple_gpu_fusion_descriptor.mlir (lit) + tests/unit/test_apple_fusion_descriptor.py (2). test_coverage regenerated; COMPILER_AUDIT updated. Follow-on: same template for the other 6 Apple fusion passes + a Python emitter stamping tessera.fusion.intent from the canonical _KNOWN_FUSION_CHAINS. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Completes the Decision #19 follow-on started in the flagship slice. C++ (Tile→Apple fusion passes): - 3 more chain passes (matmul→softmax, matmul→gelu, matmul→rmsnorm) now consume an upstream tessera.fusion.intent (source="descriptor") and fall back to structural re-discovery (source="rediscovered"), with a Decision-#21 warning on descriptor/IR disagreement — same template as matmul→softmax→matmul. - 3 composite passes (swiglu / mla_decode / native_sparse_attn) emit the descriptor with source="composite_op" (they lower a pre-fused op, which is itself the descriptor — no chain re-discovery). All 7 fused calls now carry tessera.fusion.kernel + tessera.fusion.source, so the fusion decision is first-class/auditable in Target IR. Python (emit-half): - canonical_compile.stamp_fusion_intents(module) tags the terminal op of each recognized linear chain with tessera.fusion.intent (from the canonical _KNOWN_FUSION_CHAINS), so the frontend produces descriptor-annotated IR that the C++ passes consume. Idempotent. Built clean; full tessera-ir lit 119 pass / 0 fail. Tests: tests/tessera-ir/phase8/apple_gpu_fusion_descriptor.mlir (extended to gelu + rmsnorm) and tests/unit/test_fusion_intent_emitter.py (6, incl. an emit↔consume contract guard tying the Python intents to the C++ consumers). mypy clean. COMPILER_AUDIT updated. Remaining: auto-wire stamp_fusion_intents into a Target-IR lowering path. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Closes the Decision #19 loop end-to-end: the frontend now auto-produces descriptor-annotated Graph IR for Apple targets, which the Target IR fusion passes consume (source="descriptor"). - driver.compile_graph_module calls stamp_fusion_intents(module) before rendering the Graph IR, gated to apple_gpu / apple_cpu (the only Target IR consumers today; the descriptor is backend-agnostic, extends when others consume it). Lazy import avoids the canonical_compile ↔ driver cycle. - Fix: stamp the intent into the op's MLIR `attrs` field, NOT `kwargs`. kwargs are forwarded as the op's real call arguments in the reference/runtime execution path, so a descriptor there leaked into the numpy op call (gelu(**kwargs) got an unexpected 'tessera.fusion.intent'). attrs renders only into the MLIR text the C++ passes read. Verified: apple_gpu/apple_cpu compiles carry tessera.fusion.intent on chain terminals; cpu is gated (unstamped); the previously-broken apple_cpu transformer execution test passes; 116 apple/canonical/strict-dispatch tests green; mypy clean; drift in sync. emitter tests updated to assert via attrs + that the intent never leaks into kwargs. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Closes the COMPILER_AUDIT "fusion intent is too late" item for the Apple backend: the Target IR fusion passes re-discovered the same
matmul→softmax[→matmul]/matmul→gelu/matmul→rmsnorm/ swiglu chains the canonical compile already computes (and the runtime already consumes viafusion_groups). This makes the fusion decision first-class in Target IR (Decision #19, "emit backend descriptors").C++ — all 7 Apple fusion passes emit a descriptor
Each fused call now carries
tessera.fusion.kernel+tessera.fusion.source:tessera.fusion.intent→source="descriptor"; absent it, structural re-discovery →source="rediscovered", with a Decision-Apple GPU Tier-3: conv2d via MPSGraph convolution2D #21 warning on descriptor/IR disagreement.source="composite_op"— they lower a pre-fused op (the op is the descriptor).Python — the emit-half
canonical_compile.stamp_fusion_intents(module)stampstessera.fusion.intenton each recognized chain's terminal op (from the canonical_KNOWN_FUSION_CHAINS), so the frontend produces descriptor-annotated IR. Idempotent. An emit↔consume contract test ties the Python intents to the C++ consumers so the halves can't drift.Verification
Rebuilt clean; full tessera-ir lit 119 pass / 0 fail; new lit fixture (descriptor + rediscovered across softmax/gelu/rmsnorm) +
test_apple_fusion_descriptor.py+test_fusion_intent_emitter.pygreen; mypy clean; drift gate in sync.🤖 Generated with Claude Code