diff --git a/Cargo.toml b/Cargo.toml
index f8b1503..c9a0114 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -48,6 +48,7 @@ generic-array = "0.9"
 clear_on_drop = "=0.2.3"
 subtle = { version = "0.7", features = ["generic-impls"], default-features = false }
 serde = { version = "1.0", optional = true }
+packed_simd = { version = "0.1.0", features = ["into_bits"], optional = true }
 
 [build-dependencies]
 rand = { version = "0.5", default-features = false }
@@ -57,6 +58,7 @@ generic-array = "0.9"
 clear_on_drop = "=0.2.3"
 subtle = { version = "0.7", features = ["generic-impls"], default-features = false }
 serde = { version = "1.0", optional = true }
+packed_simd = { version = "0.1.0", features = ["into_bits"], optional = true }
 
 [features]
 nightly = ["subtle/nightly", "clear_on_drop/nightly"]
@@ -71,7 +73,7 @@ u32_backend = []
 u64_backend = []
 # The AVX2 backend uses u32x8s with u64x4 products.
 # It uses the u64 code for serial operations.
-avx2_backend = ["nightly", "u64_backend"]
+avx2_backend = ["nightly", "u64_backend", "packed_simd"]
 
 # Signals that we're in the main build stage.  This is off by default,
 # to signal stage 1 of the build, where build.rs loads the library
diff --git a/build.rs b/build.rs
index 6295fdd..cc26334 100644
--- a/build.rs
+++ b/build.rs
@@ -1,6 +1,5 @@
 #![cfg_attr(all(feature = "alloc", not(feature = "std")), feature(alloc))]
 #![cfg_attr(feature = "nightly", feature(cfg_target_feature))]
-#![cfg_attr(all(feature = "nightly", feature = "avx2_backend"), feature(stdsimd))]
 #![allow(unused_variables)]
 #![allow(non_snake_case)]
 #![allow(dead_code)]
@@ -15,6 +14,9 @@ extern crate generic_array;
 extern crate rand;
 extern crate subtle;
 
+#[cfg(all(feature = "nightly", feature = "avx2_backend"))]
+extern crate packed_simd;
+
 use std::env;
 use std::fs::File;
 use std::io::Write;
diff --git a/src/backend/avx2/constants.rs b/src/backend/avx2/constants.rs
index fa31c9d..76a644a 100644
--- a/src/backend/avx2/constants.rs
+++ b/src/backend/avx2/constants.rs
@@ -10,7 +10,7 @@
 
 //! This module contains constants used by the AVX2 backend.
 
-use core::simd::u32x8;
+use packed_simd::u32x8;
 
 use backend::avx2::edwards::{CachedPoint, ExtendedPoint};
 use backend::avx2::field::FieldElement32x4;
diff --git a/src/backend/avx2/field.rs b/src/backend/avx2/field.rs
index 173d28e..6f4e1fd 100644
--- a/src/backend/avx2/field.rs
+++ b/src/backend/avx2/field.rs
@@ -40,7 +40,7 @@ const C_LANES64: u8 = 0b00_11_00_00;
 const D_LANES64: u8 = 0b11_00_00_00;
 
 use core::ops::{Add, Mul, Neg};
-use core::simd::{i32x8, u32x8, u64x4, IntoBits};
+use packed_simd::{i32x8, u32x8, u64x4, IntoBits};
 
 use backend::avx2::constants::{P_TIMES_16_HI, P_TIMES_16_LO, P_TIMES_2_HI, P_TIMES_2_LO};
 use backend::u64::field::FieldElement64;
diff --git a/src/lib.rs b/src/lib.rs
index aaf8ace..862c81a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -13,7 +13,6 @@
 #![cfg_attr(all(feature = "alloc", not(feature = "std")), feature(alloc))]
 #![cfg_attr(feature = "nightly", feature(cfg_target_feature))]
 #![cfg_attr(feature = "nightly", feature(external_doc))]
-#![cfg_attr(all(feature = "nightly", feature = "avx2_backend"), feature(stdsimd))]
 
 // Refuse to compile if documentation is missing, but only on nightly.
 //
@@ -39,6 +38,9 @@ extern crate alloc;
 #[macro_use]
 extern crate std;
 
+#[cfg(all(feature = "nightly", feature = "avx2_backend"))]
+extern crate packed_simd;
+
 extern crate rand;
 extern crate clear_on_drop;
 extern crate byteorder;