Support AArch32 Neon dotprod intrinsics.

Note that the feature detection requires a recent Linux kernel (v6.2).

3 files changed, 25 insertions, 6 deletions

diff --git a/library/stdarch/crates/std_detect/src/detect/arch/arm.rs b/library/stdarch/crates/std_detect/src/detect/arch/arm.rs
index a7dea27fb3f..fd332e0b2ca 100644
--- a/library/stdarch/crates/std_detect/src/detect/arch/arm.rs
+++ b/library/stdarch/crates/std_detect/src/detect/arch/arm.rs
@@ -22,5 +22,7 @@ features! {
     @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] sha2: "sha2";
     /// FEAT_SHA1 & FEAT_SHA256 (SHA1 & SHA2-256 instructions)
     @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] i8mm: "i8mm";
-    /// FEAT_I8MM
+    /// FEAT_I8MM (integer matrix multiplication, plus ASIMD support)
+    @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] dotprod: "dotprod";
+    /// FEAT_DotProd (Vector Dot-Product - ASIMDDP)
 }
diff --git a/library/stdarch/crates/std_detect/src/detect/os/linux/arm.rs b/library/stdarch/crates/std_detect/src/detect/os/linux/arm.rs
index 7601cf0a841..4dc9590e18b 100644
--- a/library/stdarch/crates/std_detect/src/detect/os/linux/arm.rs
+++ b/library/stdarch/crates/std_detect/src/detect/os/linux/arm.rs
@@ -17,6 +17,8 @@ pub(crate) fn detect_features() -> cache::Initializer {
     //
     // [hwcap]: https://github.com/torvalds/linux/blob/master/arch/arm/include/uapi/asm/hwcap.h
     if let Ok(auxv) = auxvec::auxv() {
+        enable_feature(&mut value, Feature::i8mm, bit::test(auxv.hwcap, 27));
+        enable_feature(&mut value, Feature::dotprod, bit::test(auxv.hwcap, 24));
         enable_feature(&mut value, Feature::neon, bit::test(auxv.hwcap, 12));
         enable_feature(&mut value, Feature::pmull, bit::test(auxv.hwcap2, 1));
         enable_feature(&mut value, Feature::crc, bit::test(auxv.hwcap2, 4));
@@ -37,6 +39,12 @@ pub(crate) fn detect_features() -> cache::Initializer {
             Feature::neon,
             c.field("Features").has("neon") && !has_broken_neon(&c),
         );
+        enable_feature(&mut value, Feature::i8mm, c.field("Features").has("i8mm"));
+        enable_feature(
+            &mut value,
+            Feature::dotprod,
+            c.field("Features").has("asimddp"),
+        );
         enable_feature(&mut value, Feature::pmull, c.field("Features").has("pmull"));
         enable_feature(&mut value, Feature::crc, c.field("Features").has("crc32"));
         enable_feature(&mut value, Feature::aes, c.field("Features").has("aes"));
diff --git a/library/stdarch/crates/std_detect/tests/cpu-detection.rs b/library/stdarch/crates/std_detect/tests/cpu-detection.rs
index 38bdb5bbd1b..f93212d24f6 100644
--- a/library/stdarch/crates/std_detect/tests/cpu-detection.rs
+++ b/library/stdarch/crates/std_detect/tests/cpu-detection.rs
@@ -20,16 +20,25 @@ fn all() {
 }
 
 #[test]
-#[cfg(all(
-    target_arch = "arm",
-    any(target_os = "linux", target_os = "android", target_os = "freebsd"),
-))]
-fn arm_linux_or_freebsd() {
+#[cfg(all(target_arch = "arm", any(target_os = "freebsd"),))]
+fn arm_freebsd() {
+    println!("neon: {}", is_arm_feature_detected!("neon"));
+    println!("pmull: {}", is_arm_feature_detected!("pmull"));
+    println!("crc: {}", is_arm_feature_detected!("crc"));
+    println!("aes: {}", is_arm_feature_detected!("aes"));
+    println!("sha2: {}", is_arm_feature_detected!("sha2"));
+}
+
+#[test]
+#[cfg(all(target_arch = "arm", any(target_os = "linux", target_os = "android"),))]
+fn arm_linux() {
     println!("neon: {}", is_arm_feature_detected!("neon"));
     println!("pmull: {}", is_arm_feature_detected!("pmull"));
     println!("crc: {}", is_arm_feature_detected!("crc"));
     println!("aes: {}", is_arm_feature_detected!("aes"));
     println!("sha2: {}", is_arm_feature_detected!("sha2"));
+    println!("dotprod: {}", is_arm_feature_detected!("dotprod"));
+    println!("i8mm: {}", is_arm_feature_detected!("i8mm"));
 }
 
 #[test]