Add missing From implementation, add simple mask API tests

Author: calebzulawski

crates/core_simd/src/masks/mod.rs

@@ -59,6 +59,24 @@ macro_rules! define_opaque_mask {
             }
         }
 
+        impl<const $lanes: usize> From<$inner_ty> for $name<$lanes>
+        where
+            BitMask<$lanes>: LanesAtMost64,
+        {
+            fn from(value: $inner_ty) -> Self {
+                Self(value)
+            }
+        }
+
+        impl<const $lanes: usize> From<$name<$lanes>> for $inner_ty
+        where
+            BitMask<$lanes>: LanesAtMost64,
+        {
+            fn from(value: $name<$lanes>) -> Self {
+                value.0
+            }
+        }
+
         impl<const $lanes: usize> Copy for $name<$lanes> where BitMask<$lanes>: LanesAtMost64 {}
 
         impl<const $lanes: usize> Clone for $name<$lanes> where BitMask<$lanes>: LanesAtMost64 {

crates/core_simd/tests/masks.rs

@@ -0,0 +1,67 @@
+use core_simd::{BitMask, Mask8, SimdMask8, SimdI8};
+use core::convert::TryFrom;
+
+#[cfg(target_arch = "wasm32")]
+use wasm_bindgen_test::*;
+
+#[cfg(target_arch = "wasm32")]
+wasm_bindgen_test_configure!(run_in_browser);
+
+#[test]
+#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+fn mask_format_round_trip() {
+    let ints = SimdI8::from_array([-1, 0, 0, -1]);
+
+    let simd_mask = SimdMask8::try_from(ints).unwrap();
+
+    let bitmask = BitMask::from(simd_mask);
+
+    let opaque_mask = Mask8::from(bitmask);
+
+    let simd_mask_returned = SimdMask8::from(opaque_mask);
+
+    let ints_returned = SimdI8::from(simd_mask_returned);
+
+    assert_eq!(ints_returned, ints);
+}
+
+macro_rules! test_mask_api {
+    { $name:ident } => {
+        #[allow(non_snake_case)]
+        mod $name {
+            #[test]
+            #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+            fn set_and_test() {
+                let values = [true, false, false, true, false, false, true, false];
+                let mut mask = core_simd::$name::<8>::splat(false);
+                for (lane, value) in values.iter().copied().enumerate() {
+                    mask.set(lane, value);
+                }
+                for (lane, value) in values.iter().copied().enumerate() {
+                    assert_eq!(mask.test(lane), value);
+                }
+            }
+
+            #[test]
+            #[should_panic]
+            fn set_invalid_lane() {
+                let mut mask = core_simd::$name::<8>::splat(false);
+                mask.set(8, true);
+                let _ = mask;
+            }
+
+            #[test]
+            #[should_panic]
+            fn test_invalid_lane() {
+                let mask = core_simd::$name::<8>::splat(false);
+                let _ = mask.test(8);
+            }
+        }
+    }
+}
+
+mod mask_api {
+    test_mask_api!{ Mask8 }
+    test_mask_api!{ SimdMask8 }
+    test_mask_api!{ BitMask }
+}