[t3dotgg]

Problem

The linux-x64 tsc that release.yml publishes is static musl. musl's memcmp, bcmp and memchr are byte loops, and its memcpy and memmove use rep movs. They cost a measurable share of a check.

Fix

The release build links lust's memfast.c (MIT, lust-lang src/runtime/memfast.c at 6ced2b86) in place of those five functions, through -Wl,--wrap. This is the memfast part of #106 without BOLT, on top of the strip and ICF recipe from #110.

• crates/ts_goport/scripts/memfast.c, memfast.sh: the C file and its build script.
• release.yml: builds the object, links it into the linux-x64 PGO tsc, and checks with nm that the five __wrap_ symbols are linked.
• License: licenses/memfast-LICENSE.txt, a NOTICE.md entry, and the npm notice.

No Rust source change, no new crate, no unsafe Rust.

Measured

Same R249 source, same PGO profile, static musl, noembed, lld ICF, stripped:

	Without memfast	With memfast
Shipped tsc	38,347,584 B	38,349,120 B (+1,536 B)
VS Code wall, default (dbook-lan, 15 rounds)	4,430.65 ms	4,265.91 ms (-3.72%)
Sentry wall	4,412.02 ms	4,221.11 ms (-4.33%)
TypeORM wall	323.12 ms	304.84 ms (-5.66%)

Single-thread instructions: Query -1.01%, Hono -1.50%, Zod -0.22%, Effect -1.28%, VS Code -3.60%, Sentry -2.47%, TypeORM -5.70%, VS Code emit -2.22%. Output (diagnostics, exits, emitted trees) is equal on every cell and on all 1,993 PGO training outputs.

---

Built and measured by GPT-6.1 Sol and checked by Claude Opus 5.5 in Claude Code.

🤖 Generated with Claude Code

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