diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index edf4396c8..50557c4bb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -230,42 +230,6 @@ jobs:
             --workspace --exclude futures-test \
             --features unstable --ignore-unknown-features
 
-  # When this job failed, run ci/no_atomic_cas.sh and commit result changes.
-  codegen:
-    runs-on: ubuntu-latest
-    permissions:
-      contents: write
-      pull-requests: write
-    steps:
-      - uses: actions/checkout@v4
-      - name: Install Rust
-        run: rustup update nightly && rustup default nightly
-      - run: ci/no_atomic_cas.sh
-      - run: git add -N . && git diff --exit-code
-        if: github.repository_owner != 'rust-lang' || github.event_name != 'schedule'
-      - id: diff
-        run: |
-          git config user.name "Taiki Endo"
-          git config user.email "te316e89@gmail.com"
-          git add -N .
-          if ! git diff --exit-code; then
-              git add .
-              git commit -m "Update no_atomic_cas.rs"
-              echo "::set-output name=success::false"
-          fi
-        if: github.repository_owner == 'rust-lang' && github.event_name == 'schedule'
-      - uses: peter-evans/create-pull-request@v5
-        with:
-          title: Update no_atomic_cas.rs
-          body: |
-            Auto-generated by [create-pull-request][1]
-            [Please close and immediately reopen this pull request to run CI.][2]
-
-            [1]: https://github.com/peter-evans/create-pull-request
-            [2]: https://github.com/peter-evans/create-pull-request/blob/HEAD/docs/concepts-guidelines.md#workarounds-to-trigger-further-workflow-runs
-          branch: update-no-atomic-cas-rs
-        if: github.repository_owner == 'rust-lang' && github.event_name == 'schedule' && steps.diff.outputs.success == 'false'
-
   miri:
     name: cargo miri test
     runs-on: ubuntu-latest
diff --git a/CHANGELOG.md b/CHANGELOG.md
index e689f3691..a1b633b2b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,11 @@
+# 0.3.30 - 2023-12-24
+
+* Add `{BiLock,SplitStream,SplitSink,ReadHalf,WriteHalf}::is_pair_of` (#2797)
+* Fix panic in `FuturesUnordered::clear` (#2809)
+* Fix panic in `AsyncBufReadExt::fill_buf` (#2801, #2812)
+* Improve support for targets without atomic CAS (#2811)
+* Remove build scripts (#2811)
+
 # 0.3.29 - 2023-10-26
 
 * Add `TryStreamExt::try_ready_chunks` (#2757)
diff --git a/ci/no_atomic_cas.sh b/ci/no_atomic_cas.sh
deleted file mode 100755
index ba0200d69..000000000
--- a/ci/no_atomic_cas.sh
+++ /dev/null
@@ -1,31 +0,0 @@
-#!/bin/bash
-set -euo pipefail
-IFS=$'\n\t'
-cd "$(dirname "$0")"/..
-
-# Update the list of targets that do not support atomic CAS operations.
-#
-# Usage:
-#    ./ci/no_atomic_cas.sh
-
-file="no_atomic_cas.rs"
-
-no_atomic_cas=()
-for target in $(rustc --print target-list); do
-    target_spec=$(rustc --print target-spec-json -Z unstable-options --target "${target}")
-    res=$(jq <<<"${target_spec}" -r 'select(."atomic-cas" == false)')
-    [[ -z "${res}" ]] || no_atomic_cas+=("${target}")
-done
-
-cat >"${file}" <<EOF
-// This file is @generated by $(basename "$0").
-// It is not intended for manual editing.
-
-const NO_ATOMIC_CAS: &[&str] = &[
-EOF
-for target in "${no_atomic_cas[@]}"; do
-    echo "    \"${target}\"," >>"${file}"
-done
-cat >>"${file}" <<EOF
-];
-EOF
diff --git a/futures-channel/Cargo.toml b/futures-channel/Cargo.toml
index 1f50e60b4..7e0e9dde2 100644
--- a/futures-channel/Cargo.toml
+++ b/futures-channel/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "futures-channel"
-version = "0.3.29"
+version = "0.3.30"
 edition = "2018"
 rust-version = "1.56"
 license = "MIT OR Apache-2.0"
@@ -22,8 +22,8 @@ unstable = []
 cfg-target-has-atomic = []
 
 [dependencies]
-futures-core = { path = "../futures-core", version = "0.3.29", default-features = false }
-futures-sink = { path = "../futures-sink", version = "0.3.29", default-features = false, optional = true }
+futures-core = { path = "../futures-core", version = "0.3.30", default-features = false }
+futures-sink = { path = "../futures-sink", version = "0.3.30", default-features = false, optional = true }
 
 [dev-dependencies]
 futures = { path = "../futures", default-features = true }
diff --git a/futures-channel/build.rs b/futures-channel/build.rs
deleted file mode 100644
index 05e0496d9..000000000
--- a/futures-channel/build.rs
+++ /dev/null
@@ -1,41 +0,0 @@
-// The rustc-cfg listed below are considered public API, but it is *unstable*
-// and outside of the normal semver guarantees:
-//
-// - `futures_no_atomic_cas`
-//      Assume the target does *not* support atomic CAS operations.
-//      This is usually detected automatically by the build script, but you may
-//      need to enable it manually when building for custom targets or using
-//      non-cargo build systems that don't run the build script.
-//
-// With the exceptions mentioned above, the rustc-cfg emitted by the build
-// script are *not* public API.
-
-#![warn(rust_2018_idioms, single_use_lifetimes)]
-
-use std::env;
-
-include!("no_atomic_cas.rs");
-
-fn main() {
-    let target = match env::var("TARGET") {
-        Ok(target) => target,
-        Err(e) => {
-            println!(
-                "cargo:warning={}: unable to get TARGET environment variable: {}",
-                env!("CARGO_PKG_NAME"),
-                e
-            );
-            return;
-        }
-    };
-
-    // Note that this is `no_*`, not `has_*`. This allows treating
-    // `cfg(target_has_atomic = "ptr")` as true when the build script doesn't
-    // run. This is needed for compatibility with non-cargo build systems that
-    // don't run the build script.
-    if NO_ATOMIC_CAS.contains(&&*target) {
-        println!("cargo:rustc-cfg=futures_no_atomic_cas");
-    }
-
-    println!("cargo:rerun-if-changed=no_atomic_cas.rs");
-}
diff --git a/futures-channel/no_atomic_cas.rs b/futures-channel/no_atomic_cas.rs
deleted file mode 120000
index 3d7380fad..000000000
--- a/futures-channel/no_atomic_cas.rs
+++ /dev/null
@@ -1 +0,0 @@
-../no_atomic_cas.rs
\ No newline at end of file
diff --git a/futures-channel/src/lib.rs b/futures-channel/src/lib.rs
index 4cd936d55..f611e6b9f 100644
--- a/futures-channel/src/lib.rs
+++ b/futures-channel/src/lib.rs
@@ -27,16 +27,16 @@
     )
 ))]
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 extern crate alloc;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod lock;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "std")]
 pub mod mpsc;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub mod oneshot;
diff --git a/futures-core/Cargo.toml b/futures-core/Cargo.toml
index 704861cc3..0e27db0a6 100644
--- a/futures-core/Cargo.toml
+++ b/futures-core/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "futures-core"
-version = "0.3.29"
+version = "0.3.30"
 edition = "2018"
 rust-version = "1.36"
 license = "MIT OR Apache-2.0"
diff --git a/futures-core/build.rs b/futures-core/build.rs
deleted file mode 100644
index 05e0496d9..000000000
--- a/futures-core/build.rs
+++ /dev/null
@@ -1,41 +0,0 @@
-// The rustc-cfg listed below are considered public API, but it is *unstable*
-// and outside of the normal semver guarantees:
-//
-// - `futures_no_atomic_cas`
-//      Assume the target does *not* support atomic CAS operations.
-//      This is usually detected automatically by the build script, but you may
-//      need to enable it manually when building for custom targets or using
-//      non-cargo build systems that don't run the build script.
-//
-// With the exceptions mentioned above, the rustc-cfg emitted by the build
-// script are *not* public API.
-
-#![warn(rust_2018_idioms, single_use_lifetimes)]
-
-use std::env;
-
-include!("no_atomic_cas.rs");
-
-fn main() {
-    let target = match env::var("TARGET") {
-        Ok(target) => target,
-        Err(e) => {
-            println!(
-                "cargo:warning={}: unable to get TARGET environment variable: {}",
-                env!("CARGO_PKG_NAME"),
-                e
-            );
-            return;
-        }
-    };
-
-    // Note that this is `no_*`, not `has_*`. This allows treating
-    // `cfg(target_has_atomic = "ptr")` as true when the build script doesn't
-    // run. This is needed for compatibility with non-cargo build systems that
-    // don't run the build script.
-    if NO_ATOMIC_CAS.contains(&&*target) {
-        println!("cargo:rustc-cfg=futures_no_atomic_cas");
-    }
-
-    println!("cargo:rerun-if-changed=no_atomic_cas.rs");
-}
diff --git a/futures-core/no_atomic_cas.rs b/futures-core/no_atomic_cas.rs
deleted file mode 120000
index 3d7380fad..000000000
--- a/futures-core/no_atomic_cas.rs
+++ /dev/null
@@ -1 +0,0 @@
-../no_atomic_cas.rs
\ No newline at end of file
diff --git a/futures-core/src/task/__internal/mod.rs b/futures-core/src/task/__internal/mod.rs
index 377f3e286..c24874228 100644
--- a/futures-core/src/task/__internal/mod.rs
+++ b/futures-core/src/task/__internal/mod.rs
@@ -1,4 +1,7 @@
-#[cfg(any(not(futures_no_atomic_cas), feature = "portable-atomic"))]
+#[cfg_attr(target_os = "none", cfg(any(target_has_atomic = "ptr", feature = "portable-atomic")))]
 mod atomic_waker;
-#[cfg(any(not(futures_no_atomic_cas), feature = "portable-atomic"))]
+#[cfg_attr(
+    target_os = "none",
+    cfg(any(target_has_atomic = "ptr", feature = "portable-atomic"))
+)]
 pub use self::atomic_waker::AtomicWaker;
diff --git a/futures-executor/Cargo.toml b/futures-executor/Cargo.toml
index 22cf99636..391a5adc4 100644
--- a/futures-executor/Cargo.toml
+++ b/futures-executor/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "futures-executor"
-version = "0.3.29"
+version = "0.3.30"
 edition = "2018"
 rust-version = "1.56"
 license = "MIT OR Apache-2.0"
@@ -16,9 +16,9 @@ std = ["futures-core/std", "futures-task/std", "futures-util/std"]
 thread-pool = ["std", "num_cpus"]
 
 [dependencies]
-futures-core = { path = "../futures-core", version = "0.3.29", default-features = false }
-futures-task = { path = "../futures-task", version = "0.3.29", default-features = false }
-futures-util = { path = "../futures-util", version = "0.3.29", default-features = false }
+futures-core = { path = "../futures-core", version = "0.3.30", default-features = false }
+futures-task = { path = "../futures-task", version = "0.3.30", default-features = false }
+futures-util = { path = "../futures-util", version = "0.3.30", default-features = false }
 num_cpus = { version = "1.8.0", optional = true }
 
 [dev-dependencies]
diff --git a/futures-io/Cargo.toml b/futures-io/Cargo.toml
index a0699de52..9911316ac 100644
--- a/futures-io/Cargo.toml
+++ b/futures-io/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "futures-io"
-version = "0.3.29"
+version = "0.3.30"
 edition = "2018"
 rust-version = "1.36"
 license = "MIT OR Apache-2.0"
diff --git a/futures-macro/Cargo.toml b/futures-macro/Cargo.toml
index f180d9e9f..6bd4baff1 100644
--- a/futures-macro/Cargo.toml
+++ b/futures-macro/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "futures-macro"
-version = "0.3.29"
+version = "0.3.30"
 edition = "2018"
 rust-version = "1.56"
 license = "MIT OR Apache-2.0"
diff --git a/futures-sink/Cargo.toml b/futures-sink/Cargo.toml
index dbf5e91be..6994ba6fc 100644
--- a/futures-sink/Cargo.toml
+++ b/futures-sink/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "futures-sink"
-version = "0.3.29"
+version = "0.3.30"
 edition = "2018"
 rust-version = "1.36"
 license = "MIT OR Apache-2.0"
diff --git a/futures-task/Cargo.toml b/futures-task/Cargo.toml
index b3bf447d3..4116a3144 100644
--- a/futures-task/Cargo.toml
+++ b/futures-task/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "futures-task"
-version = "0.3.29"
+version = "0.3.30"
 edition = "2018"
 rust-version = "1.56"
 license = "MIT OR Apache-2.0"
diff --git a/futures-task/build.rs b/futures-task/build.rs
deleted file mode 100644
index 05e0496d9..000000000
--- a/futures-task/build.rs
+++ /dev/null
@@ -1,41 +0,0 @@
-// The rustc-cfg listed below are considered public API, but it is *unstable*
-// and outside of the normal semver guarantees:
-//
-// - `futures_no_atomic_cas`
-//      Assume the target does *not* support atomic CAS operations.
-//      This is usually detected automatically by the build script, but you may
-//      need to enable it manually when building for custom targets or using
-//      non-cargo build systems that don't run the build script.
-//
-// With the exceptions mentioned above, the rustc-cfg emitted by the build
-// script are *not* public API.
-
-#![warn(rust_2018_idioms, single_use_lifetimes)]
-
-use std::env;
-
-include!("no_atomic_cas.rs");
-
-fn main() {
-    let target = match env::var("TARGET") {
-        Ok(target) => target,
-        Err(e) => {
-            println!(
-                "cargo:warning={}: unable to get TARGET environment variable: {}",
-                env!("CARGO_PKG_NAME"),
-                e
-            );
-            return;
-        }
-    };
-
-    // Note that this is `no_*`, not `has_*`. This allows treating
-    // `cfg(target_has_atomic = "ptr")` as true when the build script doesn't
-    // run. This is needed for compatibility with non-cargo build systems that
-    // don't run the build script.
-    if NO_ATOMIC_CAS.contains(&&*target) {
-        println!("cargo:rustc-cfg=futures_no_atomic_cas");
-    }
-
-    println!("cargo:rerun-if-changed=no_atomic_cas.rs");
-}
diff --git a/futures-task/no_atomic_cas.rs b/futures-task/no_atomic_cas.rs
deleted file mode 120000
index 3d7380fad..000000000
--- a/futures-task/no_atomic_cas.rs
+++ /dev/null
@@ -1 +0,0 @@
-../no_atomic_cas.rs
\ No newline at end of file
diff --git a/futures-task/src/lib.rs b/futures-task/src/lib.rs
index c72460744..33896d8b1 100644
--- a/futures-task/src/lib.rs
+++ b/futures-task/src/lib.rs
@@ -18,24 +18,24 @@ extern crate alloc;
 mod spawn;
 pub use crate::spawn::{LocalSpawn, Spawn, SpawnError};
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod arc_wake;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub use crate::arc_wake::ArcWake;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod waker;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub use crate::waker::waker;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod waker_ref;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub use crate::waker_ref::{waker_ref, WakerRef};
 
diff --git a/futures-task/src/spawn.rs b/futures-task/src/spawn.rs
index f4e63397b..4a9a45a44 100644
--- a/futures-task/src/spawn.rs
+++ b/futures-task/src/spawn.rs
@@ -168,7 +168,7 @@ mod if_alloc {
         }
     }
 
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     impl<Sp: ?Sized + Spawn> Spawn for alloc::sync::Arc<Sp> {
         fn spawn_obj(&self, future: FutureObj<'static, ()>) -> Result<(), SpawnError> {
             (**self).spawn_obj(future)
@@ -179,7 +179,7 @@ mod if_alloc {
         }
     }
 
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     impl<Sp: ?Sized + LocalSpawn> LocalSpawn for alloc::sync::Arc<Sp> {
         fn spawn_local_obj(&self, future: LocalFutureObj<'static, ()>) -> Result<(), SpawnError> {
             (**self).spawn_local_obj(future)
diff --git a/futures-test/Cargo.toml b/futures-test/Cargo.toml
index 81f00e914..8499e034d 100644
--- a/futures-test/Cargo.toml
+++ b/futures-test/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "futures-test"
-version = "0.3.29"
+version = "0.3.30"
 edition = "2018"
 rust-version = "1.56"
 license = "MIT OR Apache-2.0"
@@ -11,13 +11,13 @@ Common utilities for testing components built off futures-rs.
 """
 
 [dependencies]
-futures-core = { version = "0.3.29", path = "../futures-core", default-features = false }
-futures-task = { version = "0.3.29", path = "../futures-task", default-features = false }
-futures-io = { version = "0.3.29", path = "../futures-io", default-features = false }
-futures-util = { version = "0.3.29", path = "../futures-util", default-features = false }
-futures-executor = { version = "0.3.29", path = "../futures-executor", default-features = false }
-futures-sink = { version = "0.3.29", path = "../futures-sink", default-features = false }
-futures-macro = { version = "=0.3.29", path = "../futures-macro", default-features = false }
+futures-core = { version = "0.3.30", path = "../futures-core", default-features = false }
+futures-task = { version = "0.3.30", path = "../futures-task", default-features = false }
+futures-io = { version = "0.3.30", path = "../futures-io", default-features = false }
+futures-util = { version = "0.3.30", path = "../futures-util", default-features = false }
+futures-executor = { version = "0.3.30", path = "../futures-executor", default-features = false }
+futures-sink = { version = "0.3.30", path = "../futures-sink", default-features = false }
+futures-macro = { version = "=0.3.30", path = "../futures-macro", default-features = false }
 pin-utils = { version = "0.1.0", default-features = false }
 pin-project = "1.0.11"
 
diff --git a/futures-util/Cargo.toml b/futures-util/Cargo.toml
index 27e9e9498..dcdbce459 100644
--- a/futures-util/Cargo.toml
+++ b/futures-util/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "futures-util"
-version = "0.3.29"
+version = "0.3.30"
 edition = "2018"
 rust-version = "1.56"
 license = "MIT OR Apache-2.0"
@@ -35,12 +35,12 @@ write-all-vectored = ["io"]
 cfg-target-has-atomic = []
 
 [dependencies]
-futures-core = { path = "../futures-core", version = "0.3.29", default-features = false }
-futures-task = { path = "../futures-task", version = "0.3.29", default-features = false }
-futures-channel = { path = "../futures-channel", version = "0.3.29", default-features = false, features = ["std"], optional = true }
-futures-io = { path = "../futures-io", version = "0.3.29", default-features = false, features = ["std"], optional = true }
-futures-sink = { path = "../futures-sink", version = "0.3.29", default-features = false, optional = true }
-futures-macro = { path = "../futures-macro", version = "=0.3.29", default-features = false, optional = true }
+futures-core = { path = "../futures-core", version = "0.3.30", default-features = false }
+futures-task = { path = "../futures-task", version = "0.3.30", default-features = false }
+futures-channel = { path = "../futures-channel", version = "0.3.30", default-features = false, features = ["std"], optional = true }
+futures-io = { path = "../futures-io", version = "0.3.30", default-features = false, features = ["std"], optional = true }
+futures-sink = { path = "../futures-sink", version = "0.3.30", default-features = false, optional = true }
+futures-macro = { path = "../futures-macro", version = "=0.3.30", default-features = false, optional = true }
 slab = { version = "0.4.2", optional = true }
 memchr = { version = "2.2", optional = true }
 futures_01 = { version = "0.1.25", optional = true, package = "futures" }
diff --git a/futures-util/build.rs b/futures-util/build.rs
deleted file mode 100644
index 05e0496d9..000000000
--- a/futures-util/build.rs
+++ /dev/null
@@ -1,41 +0,0 @@
-// The rustc-cfg listed below are considered public API, but it is *unstable*
-// and outside of the normal semver guarantees:
-//
-// - `futures_no_atomic_cas`
-//      Assume the target does *not* support atomic CAS operations.
-//      This is usually detected automatically by the build script, but you may
-//      need to enable it manually when building for custom targets or using
-//      non-cargo build systems that don't run the build script.
-//
-// With the exceptions mentioned above, the rustc-cfg emitted by the build
-// script are *not* public API.
-
-#![warn(rust_2018_idioms, single_use_lifetimes)]
-
-use std::env;
-
-include!("no_atomic_cas.rs");
-
-fn main() {
-    let target = match env::var("TARGET") {
-        Ok(target) => target,
-        Err(e) => {
-            println!(
-                "cargo:warning={}: unable to get TARGET environment variable: {}",
-                env!("CARGO_PKG_NAME"),
-                e
-            );
-            return;
-        }
-    };
-
-    // Note that this is `no_*`, not `has_*`. This allows treating
-    // `cfg(target_has_atomic = "ptr")` as true when the build script doesn't
-    // run. This is needed for compatibility with non-cargo build systems that
-    // don't run the build script.
-    if NO_ATOMIC_CAS.contains(&&*target) {
-        println!("cargo:rustc-cfg=futures_no_atomic_cas");
-    }
-
-    println!("cargo:rerun-if-changed=no_atomic_cas.rs");
-}
diff --git a/futures-util/no_atomic_cas.rs b/futures-util/no_atomic_cas.rs
deleted file mode 120000
index 3d7380fad..000000000
--- a/futures-util/no_atomic_cas.rs
+++ /dev/null
@@ -1 +0,0 @@
-../no_atomic_cas.rs
\ No newline at end of file
diff --git a/futures-util/src/future/future/shared.rs b/futures-util/src/future/future/shared.rs
index ecd1b426d..9ab3b4f1d 100644
--- a/futures-util/src/future/future/shared.rs
+++ b/futures-util/src/future/future/shared.rs
@@ -37,10 +37,6 @@ impl<Fut: Future> Clone for WeakShared<Fut> {
     }
 }
 
-// The future itself is polled behind the `Arc`, so it won't be moved
-// when `Shared` is moved.
-impl<Fut: Future> Unpin for Shared<Fut> {}
-
 impl<Fut: Future> fmt::Debug for Shared<Fut> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("Shared")
diff --git a/futures-util/src/future/join_all.rs b/futures-util/src/future/join_all.rs
index 11b6f2728..79eee8dff 100644
--- a/futures-util/src/future/join_all.rs
+++ b/futures-util/src/future/join_all.rs
@@ -12,7 +12,7 @@ use core::task::{Context, Poll};
 
 use super::{assert_future, MaybeDone};
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 use crate::stream::{Collect, FuturesOrdered, StreamExt};
 
 pub(crate) fn iter_pin_mut<T>(slice: Pin<&mut [T]>) -> impl Iterator<Item = Pin<&mut T>> {
@@ -31,7 +31,7 @@ where
     kind: JoinAllKind<F>,
 }
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 pub(crate) const SMALL: usize = 30;
 
 enum JoinAllKind<F>
@@ -41,7 +41,7 @@ where
     Small {
         elems: Pin<Box<[MaybeDone<F>]>>,
     },
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     Big {
         fut: Collect<FuturesOrdered<F>, Vec<F::Output>>,
     },
@@ -57,7 +57,7 @@ where
             JoinAllKind::Small { ref elems } => {
                 f.debug_struct("JoinAll").field("elems", elems).finish()
             }
-            #[cfg(not(futures_no_atomic_cas))]
+            #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
             JoinAllKind::Big { ref fut, .. } => fmt::Debug::fmt(fut, f),
         }
     }
@@ -106,7 +106,8 @@ where
 {
     let iter = iter.into_iter();
 
-    #[cfg(futures_no_atomic_cas)]
+    #[cfg(target_os = "none")]
+    #[cfg_attr(target_os = "none", cfg(not(target_has_atomic = "ptr")))]
     {
         let kind =
             JoinAllKind::Small { elems: iter.map(MaybeDone::Future).collect::<Box<[_]>>().into() };
@@ -114,7 +115,7 @@ where
         assert_future::<Vec<<I::Item as Future>::Output>, _>(JoinAll { kind })
     }
 
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     {
         let kind = match iter.size_hint().1 {
             Some(max) if max <= SMALL => JoinAllKind::Small {
@@ -153,7 +154,7 @@ where
                     Poll::Pending
                 }
             }
-            #[cfg(not(futures_no_atomic_cas))]
+            #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
             JoinAllKind::Big { fut } => Pin::new(fut).poll(cx),
         }
     }
diff --git a/futures-util/src/future/mod.rs b/futures-util/src/future/mod.rs
index 374e36512..2d8fa4f65 100644
--- a/futures-util/src/future/mod.rs
+++ b/futures-util/src/future/mod.rs
@@ -111,13 +111,13 @@ pub use self::select_ok::{select_ok, SelectOk};
 mod either;
 pub use self::either::Either;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod abortable;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub use crate::abortable::{AbortHandle, AbortRegistration, Abortable, Aborted};
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub use abortable::abortable;
 
diff --git a/futures-util/src/future/try_join_all.rs b/futures-util/src/future/try_join_all.rs
index 506f45065..2d6a2a02c 100644
--- a/futures-util/src/future/try_join_all.rs
+++ b/futures-util/src/future/try_join_all.rs
@@ -12,7 +12,7 @@ use core::task::{Context, Poll};
 
 use super::{assert_future, join_all, IntoFuture, TryFuture, TryMaybeDone};
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 use crate::stream::{FuturesOrdered, TryCollect, TryStreamExt};
 use crate::TryFutureExt;
 
@@ -38,7 +38,7 @@ where
     Small {
         elems: Pin<Box<[TryMaybeDone<IntoFuture<F>>]>>,
     },
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     Big {
         fut: TryCollect<FuturesOrdered<IntoFuture<F>>, Vec<F::Ok>>,
     },
@@ -56,7 +56,7 @@ where
             TryJoinAllKind::Small { ref elems } => {
                 f.debug_struct("TryJoinAll").field("elems", elems).finish()
             }
-            #[cfg(not(futures_no_atomic_cas))]
+            #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
             TryJoinAllKind::Big { ref fut, .. } => fmt::Debug::fmt(fut, f),
         }
     }
@@ -121,7 +121,8 @@ where
 {
     let iter = iter.into_iter().map(TryFutureExt::into_future);
 
-    #[cfg(futures_no_atomic_cas)]
+    #[cfg(target_os = "none")]
+    #[cfg_attr(target_os = "none", cfg(not(target_has_atomic = "ptr")))]
     {
         let kind = TryJoinAllKind::Small {
             elems: iter.map(TryMaybeDone::Future).collect::<Box<[_]>>().into(),
@@ -132,7 +133,7 @@ where
         )
     }
 
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     {
         let kind = match iter.size_hint().1 {
             Some(max) if max <= join_all::SMALL => TryJoinAllKind::Small {
@@ -184,7 +185,7 @@ where
                     }
                 }
             }
-            #[cfg(not(futures_no_atomic_cas))]
+            #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
             TryJoinAllKind::Big { fut } => Pin::new(fut).poll(cx),
         }
     }
diff --git a/futures-util/src/io/copy_buf_abortable.rs b/futures-util/src/io/copy_buf_abortable.rs
index fdbc4a5f0..ed22d6233 100644
--- a/futures-util/src/io/copy_buf_abortable.rs
+++ b/futures-util/src/io/copy_buf_abortable.rs
@@ -57,7 +57,7 @@ where
 }
 
 pin_project! {
-    /// Future for the [`copy_buf()`] function.
+    /// Future for the [`copy_buf_abortable()`] function.
     #[derive(Debug)]
     #[must_use = "futures do nothing unless you `.await` or poll them"]
     pub struct CopyBufAbortable<'a, R, W: ?Sized> {
diff --git a/futures-util/src/io/fill_buf.rs b/futures-util/src/io/fill_buf.rs
index 6c14f71cd..45862b8e2 100644
--- a/futures-util/src/io/fill_buf.rs
+++ b/futures-util/src/io/fill_buf.rs
@@ -3,6 +3,7 @@ use futures_core::task::{Context, Poll};
 use futures_io::AsyncBufRead;
 use std::io;
 use std::pin::Pin;
+use std::slice;
 
 /// Future for the [`fill_buf`](super::AsyncBufReadExt::fill_buf) method.
 #[derive(Debug)]
@@ -30,19 +31,12 @@ where
         let reader = this.reader.take().expect("Polled FillBuf after completion");
 
         match Pin::new(&mut *reader).poll_fill_buf(cx) {
-            // We don't need to poll a second time for EOF, and doing so is likely to return Poll::Pending
-            Poll::Ready(Ok(&[])) => Poll::Ready(Ok(&[])),
-            // With polonius it is possible to remove this inner match and just have the correct
-            // lifetime of the reference inferred based on which branch is taken
-            Poll::Ready(Ok(_)) => match Pin::new(reader).poll_fill_buf(cx) {
-                Poll::Ready(Ok(slice)) => Poll::Ready(Ok(slice)),
-                Poll::Ready(Err(err)) => {
-                    unreachable!("reader indicated readiness but then returned an error: {:?}", err)
-                }
-                Poll::Pending => {
-                    unreachable!("reader indicated readiness but then returned pending")
-                }
-            },
+            Poll::Ready(Ok(slice)) => {
+                // With polonius it is possible to remove this lifetime transmutation and just have
+                // the correct lifetime of the reference inferred based on which branch is taken
+                let slice: &'a [u8] = unsafe { slice::from_raw_parts(slice.as_ptr(), slice.len()) };
+                Poll::Ready(Ok(slice))
+            }
             Poll::Ready(Err(err)) => Poll::Ready(Err(err)),
             Poll::Pending => {
                 this.reader = Some(reader);
diff --git a/futures-util/src/io/split.rs b/futures-util/src/io/split.rs
index 3f1b9af45..81d1e6dcb 100644
--- a/futures-util/src/io/split.rs
+++ b/futures-util/src/io/split.rs
@@ -31,6 +31,13 @@ pub(super) fn split<T: AsyncRead + AsyncWrite>(t: T) -> (ReadHalf<T>, WriteHalf<
     (ReadHalf { handle: a }, WriteHalf { handle: b })
 }
 
+impl<T> ReadHalf<T> {
+    /// Checks if this `ReadHalf` and some `WriteHalf` were split from the same stream.
+    pub fn is_pair_of(&self, other: &WriteHalf<T>) -> bool {
+        self.handle.is_pair_of(&other.handle)
+    }
+}
+
 impl<T: Unpin> ReadHalf<T> {
     /// Attempts to put the two "halves" of a split `AsyncRead + AsyncWrite` back
     /// together. Succeeds only if the `ReadHalf<T>` and `WriteHalf<T>` are
@@ -42,6 +49,13 @@ impl<T: Unpin> ReadHalf<T> {
     }
 }
 
+impl<T> WriteHalf<T> {
+    /// Checks if this `WriteHalf` and some `ReadHalf` were split from the same stream.
+    pub fn is_pair_of(&self, other: &ReadHalf<T>) -> bool {
+        self.handle.is_pair_of(&other.handle)
+    }
+}
+
 impl<T: Unpin> WriteHalf<T> {
     /// Attempts to put the two "halves" of a split `AsyncRead + AsyncWrite` back
     /// together. Succeeds only if the `ReadHalf<T>` and `WriteHalf<T>` are
diff --git a/futures-util/src/lib.rs b/futures-util/src/lib.rs
index 9a10c93c9..208eb73aa 100644
--- a/futures-util/src/lib.rs
+++ b/futures-util/src/lib.rs
@@ -329,7 +329,7 @@ pub use crate::io::{
 #[cfg(feature = "alloc")]
 pub mod lock;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod abortable;
 
diff --git a/futures-util/src/lock/bilock.rs b/futures-util/src/lock/bilock.rs
index 7ddc66ad2..a89678e05 100644
--- a/futures-util/src/lock/bilock.rs
+++ b/futures-util/src/lock/bilock.rs
@@ -149,6 +149,11 @@ impl<T> BiLock<T> {
         BiLockAcquire { bilock: self }
     }
 
+    /// Returns `true` only if the other `BiLock<T>` originated from the same call to `BiLock::new`.
+    pub fn is_pair_of(&self, other: &Self) -> bool {
+        Arc::ptr_eq(&self.arc, &other.arc)
+    }
+
     /// Attempts to put the two "halves" of a `BiLock<T>` back together and
     /// recover the original value. Succeeds only if the two `BiLock<T>`s
     /// originated from the same call to `BiLock::new`.
@@ -156,7 +161,7 @@ impl<T> BiLock<T> {
     where
         T: Unpin,
     {
-        if Arc::ptr_eq(&self.arc, &other.arc) {
+        if self.is_pair_of(&other) {
             drop(other);
             let inner = Arc::try_unwrap(self.arc)
                 .ok()
diff --git a/futures-util/src/lock/mod.rs b/futures-util/src/lock/mod.rs
index 0be72717c..8ca0ff625 100644
--- a/futures-util/src/lock/mod.rs
+++ b/futures-util/src/lock/mod.rs
@@ -3,25 +3,25 @@
 //! This module is only available when the `std` or `alloc` feature of this
 //! library is activated, and it is activated by default.
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(any(feature = "sink", feature = "io"))]
 #[cfg(not(feature = "bilock"))]
 pub(crate) use self::bilock::BiLock;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "bilock")]
 #[cfg_attr(docsrs, doc(cfg(feature = "bilock")))]
 pub use self::bilock::{BiLock, BiLockAcquire, BiLockGuard, ReuniteError};
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "std")]
 pub use self::mutex::{
     MappedMutexGuard, Mutex, MutexGuard, MutexLockFuture, OwnedMutexGuard, OwnedMutexLockFuture,
 };
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(any(feature = "bilock", feature = "sink", feature = "io"))]
 #[cfg_attr(docsrs, doc(cfg(feature = "bilock")))]
 #[cfg_attr(not(feature = "bilock"), allow(unreachable_pub))]
 mod bilock;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "std")]
 mod mutex;
diff --git a/futures-util/src/stream/futures_ordered.rs b/futures-util/src/stream/futures_ordered.rs
index 3aaef8bde..2cc144e81 100644
--- a/futures-util/src/stream/futures_ordered.rs
+++ b/futures-util/src/stream/futures_ordered.rs
@@ -19,7 +19,8 @@ pin_project! {
     struct OrderWrapper<T> {
         #[pin]
         data: T, // A future or a future's output
-        index: isize,
+        // Use i64 for index since isize may overflow in 32-bit targets.
+        index: i64,
     }
 }
 
@@ -98,8 +99,8 @@ where
 pub struct FuturesOrdered<T: Future> {
     in_progress_queue: FuturesUnordered<OrderWrapper<T>>,
     queued_outputs: BinaryHeap<OrderWrapper<T::Output>>,
-    next_incoming_index: isize,
-    next_outgoing_index: isize,
+    next_incoming_index: i64,
+    next_outgoing_index: i64,
 }
 
 impl<T: Future> Unpin for FuturesOrdered<T> {}
diff --git a/futures-util/src/stream/futures_unordered/mod.rs b/futures-util/src/stream/futures_unordered/mod.rs
index 0dbaea908..dedf75dee 100644
--- a/futures-util/src/stream/futures_unordered/mod.rs
+++ b/futures-util/src/stream/futures_unordered/mod.rs
@@ -558,20 +558,7 @@ impl<Fut> Debug for FuturesUnordered<Fut> {
 impl<Fut> FuturesUnordered<Fut> {
     /// Clears the set, removing all futures.
     pub fn clear(&mut self) {
-        self.clear_head_all();
-
-        // we just cleared all the tasks, and we have &mut self, so this is safe.
-        unsafe { self.ready_to_run_queue.clear() };
-
-        self.is_terminated.store(false, Relaxed);
-    }
-
-    fn clear_head_all(&mut self) {
-        while !self.head_all.get_mut().is_null() {
-            let head = *self.head_all.get_mut();
-            let task = unsafe { self.unlink(head) };
-            self.release_task(task);
-        }
+        *self = Self::new();
     }
 }
 
@@ -581,7 +568,11 @@ impl<Fut> Drop for FuturesUnordered<Fut> {
         // associated with it. At the same time though there may be tons of
         // wakers flying around which contain `Task<Fut>` references
         // inside them. We'll let those naturally get deallocated.
-        self.clear_head_all();
+        while !self.head_all.get_mut().is_null() {
+            let head = *self.head_all.get_mut();
+            let task = unsafe { self.unlink(head) };
+            self.release_task(task);
+        }
 
         // Note that at this point we could still have a bunch of tasks in the
         // ready to run queue. None of those tasks, however, have futures
diff --git a/futures-util/src/stream/futures_unordered/ready_to_run_queue.rs b/futures-util/src/stream/futures_unordered/ready_to_run_queue.rs
index 451870532..a924935d2 100644
--- a/futures-util/src/stream/futures_unordered/ready_to_run_queue.rs
+++ b/futures-util/src/stream/futures_unordered/ready_to_run_queue.rs
@@ -85,38 +85,25 @@ impl<Fut> ReadyToRunQueue<Fut> {
     pub(super) fn stub(&self) -> *const Task<Fut> {
         Arc::as_ptr(&self.stub)
     }
-
-    // Clear the queue of tasks.
-    //
-    // Note that each task has a strong reference count associated with it
-    // which is owned by the ready to run queue. This method just pulls out
-    // tasks and drops their refcounts.
-    //
-    // # Safety
-    //
-    // - All tasks **must** have had their futures dropped already (by FuturesUnordered::clear)
-    // - The caller **must** guarantee unique access to `self`
-    pub(crate) unsafe fn clear(&self) {
-        loop {
-            // SAFETY: We have the guarantee of mutual exclusion required by `dequeue`.
-            match self.dequeue() {
-                Dequeue::Empty => break,
-                Dequeue::Inconsistent => abort("inconsistent in drop"),
-                Dequeue::Data(ptr) => drop(Arc::from_raw(ptr)),
-            }
-        }
-    }
 }
 
 impl<Fut> Drop for ReadyToRunQueue<Fut> {
     fn drop(&mut self) {
         // Once we're in the destructor for `Inner<Fut>` we need to clear out
         // the ready to run queue of tasks if there's anything left in there.
-
-        // All tasks have had their futures dropped already by the `FuturesUnordered`
-        // destructor above, and we have &mut self, so this is safe.
+        //
+        // Note that each task has a strong reference count associated with it
+        // which is owned by the ready to run queue. All tasks should have had
+        // their futures dropped already by the `FuturesUnordered` destructor
+        // above, so we're just pulling out tasks and dropping their refcounts.
         unsafe {
-            self.clear();
+            loop {
+                match self.dequeue() {
+                    Dequeue::Empty => break,
+                    Dequeue::Inconsistent => abort("inconsistent in drop"),
+                    Dequeue::Data(ptr) => drop(Arc::from_raw(ptr)),
+                }
+            }
         }
     }
 }
diff --git a/futures-util/src/stream/mod.rs b/futures-util/src/stream/mod.rs
index 34d68a80b..2438e58b6 100644
--- a/futures-util/src/stream/mod.rs
+++ b/futures-util/src/stream/mod.rs
@@ -37,13 +37,13 @@ pub use self::stream::ReadyChunks;
 #[cfg_attr(docsrs, doc(cfg(feature = "sink")))]
 pub use self::stream::Forward;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub use self::stream::{
     BufferUnordered, Buffered, FlatMapUnordered, FlattenUnordered, ForEachConcurrent,
 };
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "sink")]
 #[cfg_attr(docsrs, doc(cfg(feature = "sink")))]
 #[cfg(feature = "alloc")]
@@ -51,9 +51,9 @@ pub use self::stream::{ReuniteError, SplitSink, SplitStream};
 
 mod try_stream;
 pub use self::try_stream::{
-    try_unfold, AndThen, ErrInto, InspectErr, InspectOk, IntoStream, MapErr, MapOk, OrElse,
-    TryCollect, TryConcat, TryFilter, TryFilterMap, TryFlatten, TryFold, TryForEach, TryNext,
-    TrySkipWhile, TryStreamExt, TryTakeWhile, TryUnfold,
+    try_unfold, AndThen, ErrInto, InspectErr, InspectOk, IntoStream, MapErr, MapOk, OrElse, TryAll,
+    TryAny, TryCollect, TryConcat, TryFilter, TryFilterMap, TryFlatten, TryFold, TryForEach,
+    TryNext, TrySkipWhile, TryStreamExt, TryTakeWhile, TryUnfold,
 };
 
 #[cfg(feature = "io")]
@@ -61,7 +61,7 @@ pub use self::try_stream::{
 #[cfg(feature = "std")]
 pub use self::try_stream::IntoAsyncRead;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub use self::try_stream::{
     TryBufferUnordered, TryBuffered, TryFlattenUnordered, TryForEachConcurrent,
@@ -105,36 +105,36 @@ pub use self::select_with_strategy::{select_with_strategy, PollNext, SelectWithS
 mod unfold;
 pub use self::unfold::{unfold, Unfold};
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod futures_ordered;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub use self::futures_ordered::FuturesOrdered;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub mod futures_unordered;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 #[doc(inline)]
 pub use self::futures_unordered::FuturesUnordered;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub mod select_all;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 #[doc(inline)]
 pub use self::select_all::{select_all, SelectAll};
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod abortable;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub use crate::abortable::{AbortHandle, AbortRegistration, Abortable, Aborted};
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub use abortable::abortable;
 
diff --git a/futures-util/src/stream/stream/mod.rs b/futures-util/src/stream/stream/mod.rs
index 3978d188f..2da7036b2 100644
--- a/futures-util/src/stream/stream/mod.rs
+++ b/futures-util/src/stream/stream/mod.rs
@@ -181,32 +181,32 @@ mod scan;
 #[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411
 pub use self::scan::Scan;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod buffer_unordered;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 #[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411
 pub use self::buffer_unordered::BufferUnordered;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod buffered;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 #[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411
 pub use self::buffered::Buffered;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub(crate) mod flatten_unordered;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 #[allow(unreachable_pub)]
 pub use self::flatten_unordered::FlattenUnordered;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 delegate_all!(
     /// Stream for the [`flat_map_unordered`](StreamExt::flat_map_unordered) method.
@@ -216,20 +216,20 @@ delegate_all!(
     where St: Stream, U: Stream, U: Unpin, F: FnMut(St::Item) -> U
 );
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod for_each_concurrent;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 #[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411
 pub use self::for_each_concurrent::ForEachConcurrent;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "sink")]
 #[cfg_attr(docsrs, doc(cfg(feature = "sink")))]
 #[cfg(feature = "alloc")]
 mod split;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "sink")]
 #[cfg_attr(docsrs, doc(cfg(feature = "sink")))]
 #[cfg(feature = "alloc")]
@@ -820,7 +820,7 @@ pub trait StreamExt: Stream {
     /// assert_eq!(output, vec![1, 2, 3, 4]);
     /// # });
     /// ```
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     #[cfg(feature = "alloc")]
     fn flatten_unordered(self, limit: impl Into<Option<usize>>) -> FlattenUnordered<Self>
     where
@@ -902,7 +902,7 @@ pub trait StreamExt: Stream {
     /// assert_eq!(vec![1usize, 2, 2, 3, 3, 3, 4, 4, 4, 4], values);
     /// # });
     /// ```
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     #[cfg(feature = "alloc")]
     fn flat_map_unordered<U, F>(
         self,
@@ -1142,7 +1142,7 @@ pub trait StreamExt: Stream {
     /// fut.await;
     /// # })
     /// ```
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     #[cfg(feature = "alloc")]
     fn for_each_concurrent<Fut, F>(
         self,
@@ -1365,7 +1365,7 @@ pub trait StreamExt: Stream {
     ///
     /// This method is only available when the `std` or `alloc` feature of this
     /// library is activated, and it is activated by default.
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     #[cfg(feature = "alloc")]
     fn buffered(self, n: usize) -> Buffered<Self>
     where
@@ -1410,7 +1410,7 @@ pub trait StreamExt: Stream {
     /// assert_eq!(buffered.next().await, None);
     /// # Ok::<(), i32>(()) }).unwrap();
     /// ```
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     #[cfg(feature = "alloc")]
     fn buffer_unordered(self, n: usize) -> BufferUnordered<Self>
     where
@@ -1577,7 +1577,7 @@ pub trait StreamExt: Stream {
     /// library is activated, and it is activated by default.
     #[cfg(feature = "sink")]
     #[cfg_attr(docsrs, doc(cfg(feature = "sink")))]
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     #[cfg(feature = "alloc")]
     fn split<Item>(self) -> (SplitSink<Self, Item>, SplitStream<Self>)
     where
diff --git a/futures-util/src/stream/stream/split.rs b/futures-util/src/stream/stream/split.rs
index e2034e0c2..1a7fdcb38 100644
--- a/futures-util/src/stream/stream/split.rs
+++ b/futures-util/src/stream/stream/split.rs
@@ -15,6 +15,13 @@ pub struct SplitStream<S>(BiLock<S>);
 
 impl<S> Unpin for SplitStream<S> {}
 
+impl<S> SplitStream<S> {
+    /// Returns `true` if the `SplitStream<S>` and `SplitSink<S>` originate from the same call to `StreamExt::split`.
+    pub fn is_pair_of<Item>(&self, other: &SplitSink<S, Item>) -> bool {
+        other.is_pair_of(&self)
+    }
+}
+
 impl<S: Unpin> SplitStream<S> {
     /// Attempts to put the two "halves" of a split `Stream + Sink` back
     /// together. Succeeds only if the `SplitStream<S>` and `SplitSink<S>` are
@@ -60,6 +67,13 @@ impl<S: Sink<Item> + Unpin, Item> SplitSink<S, Item> {
     }
 }
 
+impl<S, Item> SplitSink<S, Item> {
+    /// Returns `true` if the `SplitStream<S>` and `SplitSink<S>` originate from the same call to `StreamExt::split`.
+    pub fn is_pair_of(&self, other: &SplitStream<S>) -> bool {
+        self.lock.is_pair_of(&other.0)
+    }
+}
+
 impl<S: Sink<Item>, Item> SplitSink<S, Item> {
     fn poll_flush_slot(
         mut inner: Pin<&mut S>,
@@ -142,3 +156,69 @@ impl<T, Item> fmt::Display for ReuniteError<T, Item> {
 
 #[cfg(feature = "std")]
 impl<T: core::any::Any, Item> std::error::Error for ReuniteError<T, Item> {}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{sink::Sink, stream::StreamExt};
+    use core::marker::PhantomData;
+
+    struct NopStream<Item> {
+        phantom: PhantomData<Item>,
+    }
+
+    impl<Item> Stream for NopStream<Item> {
+        type Item = Item;
+
+        fn poll_next(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+            todo!()
+        }
+    }
+
+    impl<Item> Sink<Item> for NopStream<Item> {
+        type Error = ();
+
+        fn poll_ready(
+            self: Pin<&mut Self>,
+            _cx: &mut Context<'_>,
+        ) -> Poll<Result<(), Self::Error>> {
+            todo!()
+        }
+
+        fn start_send(self: Pin<&mut Self>, _item: Item) -> Result<(), Self::Error> {
+            todo!()
+        }
+
+        fn poll_flush(
+            self: Pin<&mut Self>,
+            _cx: &mut Context<'_>,
+        ) -> Poll<Result<(), Self::Error>> {
+            todo!()
+        }
+
+        fn poll_close(
+            self: Pin<&mut Self>,
+            _cx: &mut Context<'_>,
+        ) -> Poll<Result<(), Self::Error>> {
+            todo!()
+        }
+    }
+
+    #[test]
+    fn test_pairing() {
+        let s1 = NopStream::<()> { phantom: PhantomData };
+        let (sink1, stream1) = s1.split();
+        assert!(sink1.is_pair_of(&stream1));
+        assert!(stream1.is_pair_of(&sink1));
+
+        let s2 = NopStream::<()> { phantom: PhantomData };
+        let (sink2, stream2) = s2.split();
+        assert!(sink2.is_pair_of(&stream2));
+        assert!(stream2.is_pair_of(&sink2));
+
+        assert!(!sink1.is_pair_of(&stream2));
+        assert!(!stream1.is_pair_of(&sink2));
+        assert!(!sink2.is_pair_of(&stream1));
+        assert!(!stream2.is_pair_of(&sink1));
+    }
+}
diff --git a/futures-util/src/stream/try_stream/mod.rs b/futures-util/src/stream/try_stream/mod.rs
index 5d5702f36..7b55444b3 100644
--- a/futures-util/src/stream/try_stream/mod.rs
+++ b/futures-util/src/stream/try_stream/mod.rs
@@ -89,10 +89,10 @@ mod try_flatten;
 #[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411
 pub use self::try_flatten::TryFlatten;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod try_flatten_unordered;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 #[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411
 pub use self::try_flatten_unordered::TryFlattenUnordered;
@@ -133,26 +133,26 @@ mod try_take_while;
 #[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411
 pub use self::try_take_while::TryTakeWhile;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod try_buffer_unordered;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 #[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411
 pub use self::try_buffer_unordered::TryBufferUnordered;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod try_buffered;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 #[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411
 pub use self::try_buffered::TryBuffered;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 mod try_for_each_concurrent;
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 #[allow(unreachable_pub)] // https://github.com/rust-lang/rust/issues/57411
 pub use self::try_for_each_concurrent::TryForEachConcurrent;
@@ -551,7 +551,7 @@ pub trait TryStreamExt: TryStream {
     /// assert_eq!(Err(oneshot::Canceled), fut.await);
     /// # })
     /// ```
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     #[cfg(feature = "alloc")]
     fn try_for_each_concurrent<Fut, F>(
         self,
@@ -827,7 +827,7 @@ pub trait TryStreamExt: TryStream {
     /// assert_eq!(values, vec![Ok(1), Ok(2), Ok(4), Err(3), Err(5)]);
     /// # });
     /// ```
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     #[cfg(feature = "alloc")]
     fn try_flatten_unordered(self, limit: impl Into<Option<usize>>) -> TryFlattenUnordered<Self>
     where
@@ -1029,7 +1029,7 @@ pub trait TryStreamExt: TryStream {
     /// assert_eq!(buffered.next().await, Some(Err("error in the stream")));
     /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap();
     /// ```
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     #[cfg(feature = "alloc")]
     fn try_buffer_unordered(self, n: usize) -> TryBufferUnordered<Self>
     where
@@ -1105,7 +1105,7 @@ pub trait TryStreamExt: TryStream {
     /// assert_eq!(buffered.next().await, Some(Err("error in the stream")));
     /// # Ok::<(), Box<dyn std::error::Error>>(()) }).unwrap();
     /// ```
-    #[cfg(not(futures_no_atomic_cas))]
+    #[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
     #[cfg(feature = "alloc")]
     fn try_buffered(self, n: usize) -> TryBuffered<Self>
     where
diff --git a/futures-util/src/stream/try_stream/try_any.rs b/futures-util/src/stream/try_stream/try_any.rs
index 15adb3097..55e876be0 100644
--- a/futures-util/src/stream/try_stream/try_any.rs
+++ b/futures-util/src/stream/try_stream/try_any.rs
@@ -7,7 +7,7 @@ use futures_core::task::{Context, Poll};
 use pin_project_lite::pin_project;
 
 pin_project! {
-    /// Future for the [`any`](super::StreamExt::any) method.
+    /// Future for the [`try_any`](super::TryStreamExt::try_any) method.
     #[must_use = "futures do nothing unless you `.await` or poll them"]
     pub struct TryAny<St, Fut, F> {
         #[pin]
diff --git a/futures-util/src/stream/unfold.rs b/futures-util/src/stream/unfold.rs
index 7d8ef6bab..2f48cccb4 100644
--- a/futures-util/src/stream/unfold.rs
+++ b/futures-util/src/stream/unfold.rs
@@ -36,7 +36,7 @@ use pin_project_lite::pin_project;
 /// let stream = stream::unfold(0, |state| async move {
 ///     if state <= 2 {
 ///         let next_state = state + 1;
-///         let yielded = state  * 2;
+///         let yielded = state * 2;
 ///         Some((yielded, next_state))
 ///     } else {
 ///         None
diff --git a/futures-util/src/task/mod.rs b/futures-util/src/task/mod.rs
index 3ed4bfada..7a9e993e5 100644
--- a/futures-util/src/task/mod.rs
+++ b/futures-util/src/task/mod.rs
@@ -18,19 +18,22 @@ pub use futures_task::{FutureObj, LocalFutureObj, LocalSpawn, Spawn, SpawnError,
 pub use futures_task::noop_waker;
 pub use futures_task::noop_waker_ref;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub use futures_task::ArcWake;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub use futures_task::waker;
 
-#[cfg(not(futures_no_atomic_cas))]
+#[cfg_attr(target_os = "none", cfg(target_has_atomic = "ptr"))]
 #[cfg(feature = "alloc")]
 pub use futures_task::{waker_ref, WakerRef};
 
-#[cfg(any(not(futures_no_atomic_cas), feature = "portable-atomic"))]
+#[cfg_attr(
+    target_os = "none",
+    cfg(any(target_has_atomic = "ptr", feature = "portable-atomic"))
+)]
 pub use futures_core::task::__internal::AtomicWaker;
 
 mod spawn;
diff --git a/futures/Cargo.toml b/futures/Cargo.toml
index 96db108d3..6208f616e 100644
--- a/futures/Cargo.toml
+++ b/futures/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "futures"
-version = "0.3.29"
+version = "0.3.30"
 edition = "2018"
 rust-version = "1.56"
 license = "MIT OR Apache-2.0"
@@ -15,13 +15,13 @@ composability, and iterator-like interfaces.
 categories = ["asynchronous"]
 
 [dependencies]
-futures-core = { path = "../futures-core", version = "0.3.29", default-features = false }
-futures-task = { path = "../futures-task", version = "0.3.29", default-features = false }
-futures-channel = { path = "../futures-channel", version = "0.3.29", default-features = false, features = ["sink"] }
-futures-executor = { path = "../futures-executor", version = "0.3.29", default-features = false, optional = true }
-futures-io = { path = "../futures-io", version = "0.3.29", default-features = false }
-futures-sink = { path = "../futures-sink", version = "0.3.29", default-features = false }
-futures-util = { path = "../futures-util", version = "0.3.29", default-features = false, features = ["sink"] }
+futures-core = { path = "../futures-core", version = "0.3.30", default-features = false }
+futures-task = { path = "../futures-task", version = "0.3.30", default-features = false }
+futures-channel = { path = "../futures-channel", version = "0.3.30", default-features = false, features = ["sink"] }
+futures-executor = { path = "../futures-executor", version = "0.3.30", default-features = false, optional = true }
+futures-io = { path = "../futures-io", version = "0.3.30", default-features = false }
+futures-sink = { path = "../futures-sink", version = "0.3.30", default-features = false }
+futures-util = { path = "../futures-util", version = "0.3.30", default-features = false, features = ["sink"] }
 
 [dev-dependencies]
 futures-executor = { path = "../futures-executor", features = ["thread-pool"] }
diff --git a/futures/tests/stream_futures_unordered.rs b/futures/tests/stream_futures_unordered.rs
index b56828047..7bdf5432c 100644
--- a/futures/tests/stream_futures_unordered.rs
+++ b/futures/tests/stream_futures_unordered.rs
@@ -381,3 +381,28 @@ fn clear() {
     tasks.clear();
     assert!(!tasks.is_terminated());
 }
+
+// https://github.com/rust-lang/futures-rs/issues/2529#issuecomment-997290279
+#[test]
+fn clear_in_loop() {
+    const N: usize =
+        if cfg!(miri) || option_env!("QEMU_LD_PREFIX").is_some() { 100 } else { 10_000 };
+    futures::executor::block_on(async {
+        async fn task() {
+            let (s, r) = oneshot::channel();
+            std::thread::spawn(|| {
+                std::thread::sleep(std::time::Duration::from_micros(100));
+                let _ = s.send(());
+            });
+            r.await.unwrap()
+        }
+        let mut futures = FuturesUnordered::new();
+        for _ in 0..N {
+            for _ in 0..24 {
+                futures.push(task());
+            }
+            let _ = futures.next().await;
+            futures.clear();
+        }
+    });
+}
diff --git a/no_atomic_cas.rs b/no_atomic_cas.rs
deleted file mode 100644
index 16ec628cd..000000000
--- a/no_atomic_cas.rs
+++ /dev/null
@@ -1,17 +0,0 @@
-// This file is @generated by no_atomic_cas.sh.
-// It is not intended for manual editing.
-
-const NO_ATOMIC_CAS: &[&str] = &[
-    "armv4t-none-eabi",
-    "armv5te-none-eabi",
-    "avr-unknown-gnu-atmega328",
-    "bpfeb-unknown-none",
-    "bpfel-unknown-none",
-    "msp430-none-elf",
-    "riscv32i-unknown-none-elf",
-    "riscv32im-unknown-none-elf",
-    "riscv32imc-unknown-none-elf",
-    "thumbv4t-none-eabi",
-    "thumbv5te-none-eabi",
-    "thumbv6m-none-eabi",
-];