1 files changed, 79 insertions, 0 deletions
diff --git a/third_party/rust/packed_simd/src/api/bitmask.rs b/third_party/rust/packed_simd/src/api/bitmask.rs
new file mode 100644
index 0000000000..8f4868f328
--- /dev/null
+++ b/third_party/rust/packed_simd/src/api/bitmask.rs
@@ -0,0 +1,79 @@
+//! Bitmask API
+
+macro_rules! impl_bitmask {
+    ($id:ident | $ibitmask_ty:ident | ($set:expr, $clear:expr)
+     | $test_tt:tt) => {
+        impl $id {
+            /// Creates a bitmask with the MSB of each vector lane.
+            ///
+            /// If the vector has less than 8 lanes, the bits that do not
+            /// correspond to any vector lanes are cleared.
+            #[inline]
+            pub fn bitmask(self) -> $ibitmask_ty {
+                unsafe { codegen::llvm::simd_bitmask(self.0) }
+            }
+        }
+
+        test_if! {
+            $test_tt:
+            paste::item! {
+                #[cfg(not(
+                    // FIXME: https://github.com/rust-lang-nursery/packed_simd/issues/210
+                    target_endian = "big"
+                ))]
+                pub mod [<$id _bitmask>] {
+                    use super::*;
+                    #[cfg_attr(not(target_arch = "wasm32"), test)]
+                    #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+                    fn bitmask() {
+                        // clear all lanes
+                        let vec = $id::splat($clear as _);
+                        let bitmask: $ibitmask_ty = 0;
+                        assert_eq!(vec.bitmask(), bitmask);
+
+                        // set even lanes
+                        let mut vec = $id::splat($clear as _);
+                        for i in 0..$id::lanes() {
+                            if i % 2 == 0 {
+                                vec = vec.replace(i, $set as _);
+                            }
+                        }
+                        // create bitmask with even lanes set:
+                        let mut bitmask: $ibitmask_ty = 0;
+                        for i in 0..$id::lanes() {
+                            if i % 2 == 0 {
+                                bitmask |= 1 << i;
+                            }
+                        }
+                        assert_eq!(vec.bitmask(), bitmask);
+
+
+                        // set odd lanes
+                        let mut vec = $id::splat($clear as _);
+                        for i in 0..$id::lanes() {
+                            if i % 2 != 0 {
+                                vec = vec.replace(i, $set as _);
+                            }
+                        }
+                        // create bitmask with odd lanes set:
+                        let mut bitmask: $ibitmask_ty = 0;
+                        for i in 0..$id::lanes() {
+                            if i % 2 != 0 {
+                                bitmask |= 1 << i;
+                            }
+                        }
+                        assert_eq!(vec.bitmask(), bitmask);
+
+                        // set all lanes
+                        let vec = $id::splat($set as _);
+                        let mut bitmask: $ibitmask_ty = 0;
+                        for i in 0..$id::lanes() {
+                            bitmask |= 1 << i;
+                        }
+                        assert_eq!(vec.bitmask(), bitmask);
+                    }
+                }
+            }
+        }
+    };
+}