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| author | Cliff Click <cliffc@acm.org> | 2026-09-20 17:46:47 -0700 |
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| committer | Cliff Click <cliffc@acm.org> | 2026-09-20 17:46:47 -0700 |
| commit | 1e527b16b28f31b08cbb36b7b1bf2d689487a989 (patch) | |
| tree | eca664e141e3dd6e7091573befc1eb16d4a09bc8 /skills/chapter25-codex-notes.md | |
| parent | 6a5d13d459e40d242bea43f87a4717ad4fcf9e48 (diff) | |
| download | Simple-1e527b16b28f31b08cbb36b7b1bf2d689487a989.tar.gz Simple-1e527b16b28f31b08cbb36b7b1bf2d689487a989.zip | |
Split self-conflict phis once at a loop head
if this works, saves a copy-per-loop. If it fails, next round split as normal
Diffstat (limited to 'skills/chapter25-codex-notes.md')
| -rw-r--r-- | skills/chapter25-codex-notes.md | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/skills/chapter25-codex-notes.md b/skills/chapter25-codex-notes.md index 24a57c02..4be72a96 100644 --- a/skills/chapter25-codex-notes.md +++ b/skills/chapter25-codex-notes.md @@ -155,9 +155,9 @@ lessons rather than duplicating that history. membership, seeds, or targets when comparing chapters. - Chapter 20's corrected baseline costs one extra weighted move (354->355 over 39 compilations); document this as a correctness cost. Advanced quality - heuristics remain staged. Chapters 20-23 are now implemented; common correctness + heuristics remain staged. Chapters 20-24 are now implemented; common correctness fixes and diagnostic hooks have also been forwarded through 25 at Cliff's request. - Resume the quality/cohort/README review at 24. Chapter 21's shortened README links the retained encoding reference. + Resume the quality/cohort/README review at 25. Chapter 21's shortened README links the retained encoding reference. - Chapter 21 changed several inherited inputs/ABIs. Its Chapter20Test now freezes all 13 original programs; Chapter21AllocTest retains the four revised cases, counted with the native variants as cohort 21. On Windows the cohorts are @@ -176,6 +176,17 @@ lessons rather than duplicating that history. tests belong to 23. Grouping on/off gives identical 933 raw / 1,745 weighted moves here; report the zero gain rather than implying every heuristic helps this suite. The earlier-cohort increase includes changed optimizer behavior. +- Chapter 24 gives loop-Phi self-conflicts one cold-only splitting attempt; + remember Phi identity across rebuilt LRGs and force the ordinary fallback on + the next conflict. A backedge-only attempt can make no graph change and must + still consume that allowance. The same regression runs in 24 and 25. +- Chapter 24 preserves cohorts 20-23 and adds 67 allocations for cohort 24. + Distinguish moved inline sources from changed programs: keep the old 64-bit + Person and small emulator argument list, and attribute revised inputs to 24. + Cold-first splitting saves only 6 raw / 6 weighted moves here; the much larger + cross-chapter reduction includes optimizer changes. Its frozen String program + also found a lost null guard in the inlining dominator walk; keep that fix on + both sides when measuring the allocator heuristic. - Validate the instruction masks independently of the chosen register: a broad mask can hide behind favorable color bias. Byte/short x86 and RISC-V stores must exclude floating-point registers. Size fields such as `_sz` may hold a |