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authorHsiang-Ying Fu <66062782+fuhsnn@users.noreply.github.com>2026-09-26 06:35:22 +0800
committerGitHub <noreply@github.com>2026-09-25 15:35:22 -0700
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Extend and backport SubNode peephole (#254)
* Extend and backport SubNode peephole * Add tests * Restrict subtraction zero peepholes to integer operands Require resolved integer mode in chapter 25 so zero subtraction preserves floating-point signed zero. Keep nonnumeric operands in the graph for subtraction diagnostics. Add signed-zero coverage from chapter 12 and null-subtraction diagnostics from chapter 22. Confirmed the regressions fail on the original PR. Full Make suites pass in chapters 4-25 (5462 tests), including fresh chapter 25 sys.o compilation. --------- Co-authored-by: Cliff Click <cliffc@acm.org>
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@@ -218,6 +218,7 @@ Unresolved reproductions have been promoted to the pending queue above.
| Completed work | Scope and evidence retained |
|---|---|
+| #254 subtraction zero identities | Require integer operands in 4-25 and resolved integer mode in 25. Preserve floating-point signed zero and subtraction diagnostics. `Chapter12Test.testSubZeroFloat` runs in 12-25; `Chapter22Test.testSubZeroTypeError` runs in 22-25. Against the original PR, the signed-zero test fails in 25 and the diagnostic test fails in 22-25. Full Make suites passed in every chapter 4-25 on 2026-09-25, including fresh `sys.o` compilation in 25. |
| Short type extrema | Memory, struct and memory-pointer BOT/TOP names from 10; function-pointer names from 18. Exact types use shortcuts in ordinary, nested and HTML prints; precise types retain their details. Full Make suites in 10-20 and type/frontend suites in 21-25 passed; canonical/nested print checks passed in 10-25. |
| Integer result types | Integer-op fallbacks in 4-13 and remaining unary cases through 17 retain integer types; 5's Phis meet their data-input types. Full Make suites in 4-17 passed, plus a chapter 5 snapshot check of Phi/Add types. Integer BOT starts in 4; later arithmetic already has typed fallbacks, with unresolved bimorphic modes preserved in 25. |
| B14 cyclic leaf-kind equality | 23-24 backport; 25 already correct. Cyclic equality starts in 23. `TypeTest.testCyclicLeafKinds` fails before the fix; earlier interned-child equality already checks kinds. Full affected suites passed. |