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diff --git a/docs/chapter-backports.md b/docs/chapter-backports.md index a8be1e24..53fd6a9c 100644 --- a/docs/chapter-backports.md +++ b/docs/chapter-backports.md @@ -109,6 +109,34 @@ Existing spill expectations changed in the String fixture: These records describe completed work, not outstanding implementation tasks. Historical chapter numbers and measurements below refer to their original runs. +### Loop store sinking: Chapters 17b-25 (2026-10-05) + +The Chapter 17b presentation peephole is forwarded through Chapter 25. A loop +memory Phi whose backedge is a sole-use Store becomes a Store of a scalar Phi. +An entry Load preserves zero-trip behavior. The address must be a constant +field offset of an allocation dominating the loop; array elements are excluded. +Wait for parallel bulk-memory splitting before replacing the precise Phi. +Chapter 25 preserves the Store's frozen width and excludes unresolved aliases, +undecided widths, and constructor initialization Stores. + +Existing suites exposed three small supporting fixes: Loads through a TOP +pointer stay TOP in 17b-23; Chapter 25 keeps a MemMerge alive while flattening a +dead memory cycle; the shared printer computes placement for constants even +when they have no cached block. Existing graph assertions now count reachable +definitions and allow scalar field Phis. The synthetic-exit fixture uses a +varying pointer so it still exercises loop-carried memory after store sinking. +No new test methods were added for the forward port. Spill expectations were +updated for the changed graphs, including the infinite-loop, String, and Scan +fixtures; runtime and register-correctness assertions remain enabled. + +Validation: full Make suites pass in 17b (306 including its fuzzer wrapper), +18 (339), 19 (383), 20 (405), 21 (444), 22 (465), 23 (487), and 24 (517), plus +the separate fuzzer wrappers in 18-24. Chapter 25 passes all six suite groups +(403, 39, 9, 23, 1, and 19), including rebuilt sys.o, native execution, and +the existing fuzzer seeds. Shared printer and ISA checks pass. Logs are in +`build/rebase-talk/loop-store-*.log`. The presentation example still has 333 +capture frames and 52 final nodes, with both Totals stores outside the loop. + ### Shared ISA encoders and evaluators: Chapters 21-25 Issue #257's extraction is implemented in [`isa/`](../isa/README.md). `X86` |