Module detect 

Available on x86-64 or x86 or AArch64 only.

Optimized feature detection macros.

These macros combine compile-time and runtime feature detection, avoiding redundant runtime checks when features are compile-time known.

Important Limitation

cfg!(target_feature) is evaluated at crate level, not function level. This means the compile-time optimization does NOT work inside functions marked with #[target_feature(enable = "...")] unless the feature is also enabled globally via -C target-feature or -C target-cpu.

For eliminating checks inside multiversioned functions, use tokens instead - they provide type-level proof that a feature is available.

Functions

check_avx2_availablex86-64

Helper function for verifying assembly output. When compiled with +avx2, this should contain no cpuid or function calls.

check_avx512f_availablex86-64

Helper function for verifying assembly output. When compiled with +avx512f, this should contain no cpuid or function calls.

check_fma_availablex86-64

Helper function for verifying assembly output. When compiled with +fma, this should contain no cpuid or function calls.