Fix support for loongarch.

.github/workflows/loongarch.yml

@@ -0,0 +1,64 @@
+name: Rust
+
+on: [pull_request, workflow_dispatch]
+
+env:
+  TOOLCHAIN_HOME: /opt/cross-tools
+  TARGET: loongarch64-unknown-linux-gnu
+  DEBIAN_FRONTEND: noninteractive
+
+jobs:
+  loongarch:
+    name: LoongArch64
+    runs-on: ubuntu-latest
+    continue-on-error: ${{ matrix.rust == 'nightly' }}
+    strategy:
+      matrix:
+        rust:
+          - stable
+          - nightly
+
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v4
+
+    - name: Linux Install Rust toolchain
+      uses: dtolnay/rust-toolchain@master
+      with:
+        toolchain: ${{ matrix.rust }}
+        targets: "${TARGET}"
+
+    - name: Install Cross Toolchain
+      run: |
+        # NOTE: Update this periodically
+        release="2025.08.08"
+        filename="loongarch64.tar.xz"
+        url="https://github.com/loongson/build-tools/releases/download/${release}/x86_64-cross-tools-loongarch64-binutils_2.45-gcc_15.1.0-glibc_2.42.tar.xz"
+
+        wget "${url}" -O "${filename}"
+        tar -xf "${filename}"
+        sudo mv "cross-tools" "${TOOLCHAIN_HOME}"
+        rm "${filename}"
+
+        "${TOOLCHAIN_HOME}/bin/loongarch64-unknown-linux-gnu-gcc" --version
+
+    - name: Install Qemu Runner
+      run: |
+        sudo apt update && sudo apt install qemu-user -y --no-install-recommends
+        qemu-loongarch64 --version
+
+    - name: Build and Test Library
+      run: |
+        export CC_loongarch64_unknown_linux_gnu="${TOOLCHAIN_HOME}/bin/loongarch64-unknown-linux-gnu-gcc"
+        export CXX_loongarch64_unknown_linux_gnu="${TOOLCHAIN_HOME}/bin/loongarch64-unknown-linux-gnu-g++"
+        export AR_loongarch64_unknown_linux_gnu="${TOOLCHAIN_HOME}/bin/loongarch64-unknown-linux-gnu-gcc-ar"
+        export CARGO_TARGET_LOONGARCH64_UNKNOWN_LINUX_GNU_LINKER="${TOOLCHAIN_HOME}/bin/loongarch64-unknown-linux-gnu-gcc"
+        export CARGO_TARGET_LOONGARCH64_UNKNOWN_LINUX_GNU_RUNNER="qemu-loongarch64 -L ${TOOLCHAIN_HOME}/target"
+
+        # NOTE: The qemu runner does not seem to work for this architecture.
+        cargo build --target "${TARGET}"
+        cargo test --target "${TARGET}"
+
+        cd devel
+        cargo build --target "${TARGET}"
+        cargo test --target "${TARGET}"

.github/workflows/rust.yml

@@ -122,9 +122,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Linux Install Rust toolchain
-        uses: dtolnay/rust-toolchain@master
-        with:
-            toolchain: 1.75.0
+        uses: dtolnay/rust-toolchain@stable
 
       - name: Build, Check, and Test
         run: |

build.rs

@@ -1,5 +1,7 @@
 fn main() {
     let version = rustc_version::version().unwrap();
+    let version_meta = rustc_version::version_meta().unwrap();
+    let support_unstable = version_meta.channel == rustc_version::Channel::Nightly;
 
     if version >= rustc_version::Version::parse("1.63.0").unwrap() {
         println!("cargo:rustc-cfg=has_aarch64_intrinsics");
@@ -8,4 +10,8 @@ fn main() {
     if version >= rustc_version::Version::parse("1.70.0").unwrap() {
         println!("cargo:rustc-cfg=has_x86_intrinsics");
     }
+
+    if support_unstable && version >= rustc_version::Version::parse("1.89.0").unwrap() {
+        println!("cargo:rustc-cfg=has_loongarch_intrinsics");
+    }
 }

src/binary16/arch.rs

@@ -33,6 +33,7 @@ macro_rules! convert_fn {
                 $aarch64
             }
             else if #[cfg(all(
+                has_loongarch_intrinsics,
                 target_arch = "loongarch64",
                 target_feature = "lsx"
             ))] {
@@ -65,6 +66,7 @@ macro_rules! convert_fn {
                 }
             }
             else if #[cfg(all(
+                has_loongarch_intrinsics,
                 feature = "std",
                 target_arch = "loongarch64",
             ))] {

src/binary16/arch/loongarch64.rs

@@ -1,3 +1,6 @@
+#![cfg(has_loongarch_intrinsics)]
+#![allow(unknown_lints)]
+
 #[cfg(target_arch = "loongarch64")]
 use core::arch::loongarch64::{lsx_vfcvt_h_s, lsx_vfcvtl_s_h, m128, m128i};
 use core::{mem::MaybeUninit, ptr};

src/lib.rs

@@ -60,8 +60,10 @@
 //! [`std`]: https://doc.rust-lang.org/std/
 //! [`binary16`]: https://en.wikipedia.org/wiki/Half-precision_floating-point_format
 //! [`bfloat16`]: https://en.wikipedia.org/wiki/Bfloat16_floating-point_format
+
 #![allow(clippy::verbose_bit_mask, clippy::cast_lossless, unexpected_cfgs)]
 #![cfg_attr(not(feature = "std"), no_std)]
+#![cfg_attr(all(target_arch = "loongarch64", has_loongarch_intrinsics), feature(stdarch_loongarch))]
 #![doc(html_root_url = "https://docs.rs/float16/0.1.6")]
 #![doc(test(attr(deny(warnings), allow(unused))))]
 // Until updated to use newly stabilized `from_bits`, disable new lint warning about the transmutes