# Enable CPU intrinsics for AES-NI + SSSE3 on x86_64 targets only.
#
# The qbz-cmaf crate does AES-128-CTR decrypt on every offline-cached
# audio frame. Without AES-NI the decrypt falls back to a software
# implementation that hits ~10 MB/s on a modern CPU; with AES-NI it
# clears 400+ MB/s. For HiRes (200 MB+ tracks) this is the difference
# between a 20-second gap and a sub-second one.
#
# What we need is ONLY the AES-NI instruction set compiled in. The
# `aes` crate uses `cpufeatures::new!` to do a runtime CPUID check
# before dispatching to the hardware path, so as long as the AES-NI
# code is present in the binary, CPUs without AES-NI fall back to the
# software implementation gracefully — no crash, just slower decrypt.
#
# `target-feature=+aes,+ssse3` is what enables that compile-in.
# SSSE3 has been in every x86_64 CPU since 2006 (Core 2).
#
# We deliberately do NOT set `target-cpu=x86-64-v3` (Haswell baseline,
# 2013). v3 includes AVX2/BMI2/FMA/LZCNT/MOVBE and LLVM will freely
# emit those instructions anywhere in the binary — including the
# startup path, long before CMAF runs. On pre-Haswell CPUs (Sandy
# Bridge 2011, Ivy Bridge 2012, AMD Bulldozer/Piledriver) the process
# dies with SIGILL at launch. See issue #353 (Linux, Sandy Bridge) and
# discussion #343 (macOS, 2012 MacBookPro9,1 / Ivy Bridge). Raising
# the baseline gave no CMAF speedup — the perf win came entirely from
# `+aes` — so we keep the AES-NI path and drop the incompatible
# baseline.
#
# If a future hot loop ever warrants AVX2/BMI2, the correct pattern is
# per-function `#[target_feature]` with runtime dispatch (as the `aes`
# crate already does via `cpufeatures`), NOT a global microarch bump
# that silently breaks older hardware.
#
# IMPORTANT: these flags MUST be scoped to x86_64 targets. Using
# `[build] rustflags = ...` applies them to every target, which on
# aarch64-apple-darwin (and any other ARM target) corrupts the CPU
# feature inference inside the `ring` crate and fails the build with
# `assertion failed: CAPS_STATIC == MIN_STATIC_FEATURES`. ARM targets
# get their own AES/crypto extensions automatically via `aes` crate's
# armv8 path — we don't need to force anything there.
[target.'cfg(target_arch = "x86_64")']
rustflags = ["-C", "target-feature=+aes,+ssse3"]