From ea7e291e6a11ddd78cdf5eac98b3659294813fa4 Mon Sep 17 00:00:00 2001
From: czoli1976 <64466170+czoli1976@users.noreply.github.com>
Date: Sun, 3 May 2026 16:19:37 +0100
Subject: [PATCH] build(deps): enable rustfft `wasm_simd` feature
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`wasm_simd` is cfg-gated inside rustfft to wasm32 + the feature flag,
so it's a no-op on non-wasm targets — safe to enable unconditionally
for the cdylib/staticlib/native bin matrix.

On `wasm32-unknown-unknown` with `+simd128`, this lets rustfft's
auto-planner pick `FftPlannerWasmSimd` instead of falling back to
the scalar planner. STFT/iSTFT in DFN3 then use v128 butterflies.

Net effect on DFN3 streaming RTF: within noise (Chromium 0.066 -> 0.066,
both same-machine back-to-back). The FFT sizes used by DFN3 (480 / 960
mixed-radix) don't materially benefit, but the feature is bit-exact,
zero-risk, and helpful to other downstream rustfft consumers (apps
with larger or power-of-2 FFT sizes).

Wasm size cost: +400 KB compressed.
---
 libDF/Cargo.toml | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/libDF/Cargo.toml b/libDF/Cargo.toml
index c0f3271ef..4e9eb8c79 100644
--- a/libDF/Cargo.toml
+++ b/libDF/Cargo.toml
@@ -94,7 +94,11 @@ wasm = [
 hdf5-static = ["hdf5?/static"]
 
 [dependencies]
-rustfft = "^6.1.0"
+# `wasm_simd` is a no-op on non-wasm targets (cfg-gated inside rustfft), so
+# enabling it unconditionally is safe for the cdylib/staticlib/native bin
+# matrix. On `wasm32-unknown-unknown` with `+simd128` it lets rustfft's
+# `FftPlannerWasmSimd` use v128 butterflies instead of scalar fallback.
+rustfft = { version = "^6.1.0", features = ["wasm_simd"] }
 realfft = "^3.1.0"
 itertools = "0.12"
 num-complex = { version = "^0.4", features = ["serde"] }