LLVM-in-Rust

Execute Milestone Z release-candidate burn-in work for issue

Implement Milestone I sub-issues — floating-point arithmetic lowering (SSE2/NEON/RV F+D extensions, FP register class, FP calling convention) and non-promotable memory (stack frame, SP-relative alloca/load/store, non-constant GEP) across all backends.

Implement issue

Implement issue

Implement issue

Implement and verify issue

Implement issue

Implement issue

Implement issue

Implement issue

Migrate this Rust workspace from nightly-only requirements to stable-compatible development and CI. Use when removing `#![feature(...)]`, replacing unstable benchmark harness usage, validating `cargo +stable build/test`, and updating docs/CI for issue

Implement issue