Fil-C adds statically validated memory-safe inline assembly

Category: Engineering post
Status: discussion
Sources: fil-c.org, HN
Summary: Fil-C, a memory-safe C and C++ compiler, documented a pre-release capability (release v0.679) for safe inline assembly. Its FilPizlonator instrumentation pass parses inline-assembly strings and their constraints at the LLVM IR level and cross-checks that the declared register and flag effects match the actual instructions; a mismatch triggers a runtime panic with diagnostics rather than a silent miscompilation. The author describes an agent-driven workflow used to allowlist hundreds of pre-AVX-512 x86-64 instructions.
Why it matters: Inline assembly is a common escape hatch from memory-safety guarantees, so validating it closes a gap in memory-safe C and C++ migration paths.