inlinealways

Inlinealways refers to a compiler directive or attribute used to request that a function be inlined at all opportunities during optimization. It is a conveys-through-hint mechanism rather than a guaranteed behavior, helping the compiler eliminate call overhead and enable further optimizations, while risking increased code size.

The exact syntax and naming vary by language. In Rust, the attribute is #[inline(always)] placed on a function to strongly suggest inlining. In C and C++, inlining is requested with inline, and forcing inlining often uses attributes such as __attribute__((always_inline)) with GCC/Clang or __forceinline in MSVC. Some languages provide top-level pragmas or other annotations to achieve a similar effect; the general idea is to override typical inlining heuristics in favor of aggressive inlining for small, frequently called functions.

When to use inlinealways: it is typically considered for hot paths where a small function wraps a primitive operation or simple logic, and where inlining can reduce function call overhead or enable constant folding and other optimizations. It is not a universal performance win; increasing inlined code can balloon code size, reduce instruction cache efficiency, and complicate debugging. Therefore, profiling and careful testing are advised, and the directive should be applied selectively to performance-critical, well-understood cases.

Limitations and alternatives: since behavior is not portable across languages and toolchains, inlinealways may be ignored or overridden by the compiler if inlining would violate constraints or bloat code excessively. It is related to but distinct from more general inlining hints (inline or always inlining at the compiler’s discretion) and noinline controls.