compiler-builtins subtree update

library/compiler-builtins/.github/workflows/main.yaml

@@ -11,11 +11,12 @@ concurrency:
 
 env:
   CARGO_TERM_COLOR: always
+  CARGO_TERM_VERBOSE: true
   LIBM_BUILD_VERBOSE: true
   RUSTDOCFLAGS: -Dwarnings
-  RUSTFLAGS: -Dwarnings
+  RUSTFLAGS: -Dwarnings -Dlinker_messages
   RUST_BACKTRACE: full
-  BENCHMARK_RUSTC: nightly-2026-08-05 # Pin the toolchain for reproducable results
+  BENCHMARK_RUSTC: nightly-2026-08-19 # Pin the toolchain for reproducable results
 
 defaults:
   run:
@@ -91,6 +92,8 @@ jobs:
         #   os: ["self-hosted", "linux", "riscv64"]
         - target: riscv64gc-unknown-linux-gnu
           os: ubuntu-26.04
+        - target: s390x-unknown-linux-gnu
+          os: self-hosted-linux-s390x-resolute-large-rust # resolute == ubuntu-26.04
         - target: s390x-unknown-linux-gnu
           os: ubuntu-24.04-s390x
         - target: thumbv6m-none-eabi
@@ -111,9 +114,10 @@ jobs:
           os: windows-2025-vs2026
         - target: x86_64-pc-windows-msvc
           os: windows-2025-vs2026
-        - target: i686-pc-windows-gnu
-          os: windows-2025-vs2026
-          channel: nightly-i686-gnu
+        # FIXME(rust-lang/compiler-builtins#1306): disabled due to broken environment
+        # - target: i686-pc-windows-gnu
+        #   os: windows-2025-vs2026
+        #   channel: nightly-i686-gnu
         - target: x86_64-pc-windows-gnu
           os: windows-2025-vs2026
           channel: nightly-x86_64-gnu
@@ -132,26 +136,20 @@ jobs:
         lscpu || (sysctl -a | grep cpu) || true
         echo "home: ${HOME:-not found}"
         pwd
-
-    # Native ppc and s390x runners don't have rustup by default
-    - name: Install rustup
-      if: matrix.os == 'ubuntu-26.04-ppc64le' || matrix.os == 'ubuntu-26.04-s390x'
-      run: sudo apt-get update && sudo apt-get install -y rustup
-
     - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       with: { persist-credentials: false }
-    - name: Install Rust (rustup)
-      run: |
-        channel="nightly"
-        # Account for channels that have required components (MinGW)
-        [ -n "$JOB_CHANNEL" ] && channel="$JOB_CHANNEL"
-        rustup update "$channel" --no-self-update
-        rustup default "$channel"
-        rustup target add "$JOB_TARGET"
+
+    - name: Set up dependencies and Rust
+      run: ./ci/install-test-deps.sh "$JOB_TARGET" "$JOB_CHANNEL" "$RUN_IN_DOCKER"
 
     - uses: taiki-e/install-action@7f4eb899022d8fe70b20c4f3de697aa85c309026 # v2.85.11
+      continue-on-error: true
       with:
         tool: nextest@0.9.131
+        # On platforms without prebuilts, nextest can be installed system-wide
+        # or omitted. Building it probably takes longer than running tests
+        # without it
+        fallback: none
 
     - uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
       with:
@@ -172,7 +170,7 @@ jobs:
       uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
       with:
         path: compiler-rt
-        key: ${{ runner.os }}-compiler-rt-${{ hashFiles('ci/download-compiler-rt.sh', 'ci/compiler-rt-patches') }}
+        key: ${{ runner.os }}-compiler-rt-${{ hashFiles('ci/download-compiler-rt.sh') }}
     - name: Download compiler-rt reference sources
       if: steps.cache-compiler-rt.outputs.cache-hit != 'true'
       run: ./ci/download-compiler-rt.sh
@@ -345,7 +343,7 @@ jobs:
   msrv:
     name: Check libm MSRV
     runs-on: ubuntu-26.04
-    timeout-minutes: 10
+    timeout-minutes: 20
     env:
       RUSTFLAGS: # No need to check warnings on old MSRV, unset `-Dwarnings`
     steps:
@@ -358,7 +356,7 @@ jobs:
         rustup update "$msrv" --no-self-update && rustup default "$msrv"
     - uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
     - run: |
-        # FIXME(msrv): Remove the workspace Cargo.toml so 1.63 cargo doesn't see
+        # FIXME(msrv): Remove the workspace Cargo.toml so MSRV cargo doesn't see
         # `edition = "2024"` and get spooked.
         rm Cargo.toml
         cargo build --manifest-path libm/Cargo.toml

library/compiler-builtins/builtins-test/Cargo.toml

@@ -37,6 +37,10 @@ icount = ["dep:gungraun"]
 benchmarking-reports = ["walltime", "criterion/plotters", "criterion/html_reports"]
 walltime = ["dep:criterion"]
 
+[lints.clippy]
+# This sometimes reads better
+needless-range-loop = "allow"
+
 [[bench]]
 name = "float_add"
 harness = false

library/compiler-builtins/builtins-test/benches/mem.rs

@@ -1,72 +1,39 @@
 #![feature(test)]
 
 extern crate test;
+use builtins_test::mem::AlignedSlice;
 use test::{Bencher, black_box};
 
 extern crate compiler_builtins;
 use compiler_builtins::mem::{memcmp, memcpy, memmove, memset};
 
-const WORD_SIZE: usize = core::mem::size_of::<usize>();
-
-struct AlignedVec {
-    vec: Vec<usize>,
-    size: usize,
-}
-
-impl AlignedVec {
-    fn new(fill: u8, size: usize) -> Self {
-        let mut broadcast = fill as usize;
-        let mut bits = 8;
-        while bits < WORD_SIZE * 8 {
-            broadcast |= broadcast << bits;
-            bits *= 2;
-        }
-
-        let vec = vec![broadcast; (size + WORD_SIZE - 1) & !WORD_SIZE];
-        AlignedVec { vec, size }
-    }
-}
-
-impl core::ops::Deref for AlignedVec {
-    type Target = [u8];
-    fn deref(&self) -> &[u8] {
-        unsafe { core::slice::from_raw_parts(self.vec.as_ptr() as *const u8, self.size) }
-    }
-}
-
-impl core::ops::DerefMut for AlignedVec {
-    fn deref_mut(&mut self) -> &mut [u8] {
-        unsafe { core::slice::from_raw_parts_mut(self.vec.as_mut_ptr() as *mut u8, self.size) }
-    }
-}
-
 fn memcpy_builtin(b: &mut Bencher, n: usize, offset1: usize, offset2: usize) {
-    let v1 = AlignedVec::new(1, n + offset1);
-    let mut v2 = AlignedVec::new(0, n + offset2);
+    let v1 = AlignedSlice::new(1, n, offset1);
+    let mut v2 = AlignedSlice::new(0, n, offset2);
     b.bytes = n as u64;
     b.iter(|| {
-        let src: &[u8] = black_box(&v1[offset1..]);
-        let dst: &mut [u8] = black_box(&mut v2[offset2..]);
+        let src: &[u8] = black_box(&v1);
+        let dst: &mut [u8] = black_box(&mut v2);
         dst.copy_from_slice(src);
     })
 }
 
 fn memcpy_rust(b: &mut Bencher, n: usize, offset1: usize, offset2: usize) {
-    let v1 = AlignedVec::new(1, n + offset1);
-    let mut v2 = AlignedVec::new(0, n + offset2);
+    let v1 = AlignedSlice::new(1, n, offset1);
+    let mut v2 = AlignedSlice::new(0, n, offset2);
     b.bytes = n as u64;
     b.iter(|| {
-        let src: &[u8] = black_box(&v1[offset1..]);
-        let dst: &mut [u8] = black_box(&mut v2[offset2..]);
+        let src: &[u8] = black_box(&v1);
+        let dst: &mut [u8] = black_box(&mut v2);
         unsafe { memcpy(dst.as_mut_ptr(), src.as_ptr(), n) }
     })
 }
 
 fn memset_builtin(b: &mut Bencher, n: usize, offset: usize) {
-    let mut v1 = AlignedVec::new(0, n + offset);
+    let mut v1 = AlignedSlice::new(0, n, offset);
     b.bytes = n as u64;
     b.iter(|| {
-        let dst: &mut [u8] = black_box(&mut v1[offset..]);
+        let dst: &mut [u8] = black_box(&mut v1);
         let val: u8 = black_box(27);
         for b in dst {
             *b = val;
@@ -75,18 +42,18 @@ fn memset_builtin(b: &mut Bencher, n: usize, offset: usize) {
 }
 
 fn memset_rust(b: &mut Bencher, n: usize, offset: usize) {
-    let mut v1 = AlignedVec::new(0, n + offset);
+    let mut v1 = AlignedSlice::new(0, n, offset);
     b.bytes = n as u64;
     b.iter(|| {
-        let dst: &mut [u8] = black_box(&mut v1[offset..]);
+        let dst: &mut [u8] = black_box(&mut v1);
         let val = black_box(27);
         unsafe { memset(dst.as_mut_ptr(), val, n) }
     })
 }
 
 fn memcmp_builtin(b: &mut Bencher, n: usize) {
-    let v1 = AlignedVec::new(0, n);
-    let mut v2 = AlignedVec::new(0, n);
+    let v1 = AlignedSlice::new(0, n, 0);
+    let mut v2 = AlignedSlice::new(0, n, 0);
     v2[n - 1] = 1;
     b.bytes = n as u64;
     b.iter(|| {
@@ -97,20 +64,20 @@ fn memcmp_builtin(b: &mut Bencher, n: usize) {
 }
 
 fn memcmp_builtin_unaligned(b: &mut Bencher, n: usize) {
-    let v1 = AlignedVec::new(0, n);
-    let mut v2 = AlignedVec::new(0, n);
+    let v1 = AlignedSlice::new(0, n, 0);
+    let mut v2 = AlignedSlice::new(0, n, 1);
     v2[n - 1] = 1;
     b.bytes = n as u64;
     b.iter(|| {
-        let s1: &[u8] = black_box(&v1[0..]);
-        let s2: &[u8] = black_box(&v2[1..]);
+        let s1: &[u8] = black_box(&v1);
+        let s2: &[u8] = black_box(&v2);
         s1.cmp(s2)
     })
 }
 
 fn memcmp_rust(b: &mut Bencher, n: usize) {
-    let v1 = AlignedVec::new(0, n);
-    let mut v2 = AlignedVec::new(0, n);
+    let v1 = AlignedSlice::new(0, n, 0);
+    let mut v2 = AlignedSlice::new(0, n, 0);
     v2[n - 1] = 1;
     b.bytes = n as u64;
     b.iter(|| {
@@ -121,19 +88,20 @@ fn memcmp_rust(b: &mut Bencher, n: usize) {
 }
 
 fn memcmp_rust_unaligned(b: &mut Bencher, n: usize) {
-    let v1 = AlignedVec::new(0, n);
-    let mut v2 = AlignedVec::new(0, n);
+    let v1 = AlignedSlice::new(0, n, 0);
+    let mut v2 = AlignedSlice::new(0, n, 1);
     v2[n - 1] = 1;
     b.bytes = n as u64;
     b.iter(|| {
-        let s1: &[u8] = black_box(&v1[0..]);
-        let s2: &[u8] = black_box(&v2[1..]);
-        unsafe { memcmp(s1.as_ptr(), s2.as_ptr(), n - 1) }
+        let s1: &[u8] = black_box(&v1);
+        let s2: &[u8] = black_box(&v2);
+        unsafe { memcmp(s1.as_ptr(), s2.as_ptr(), n) }
     })
 }
 
 fn memmove_builtin(b: &mut Bencher, n: usize, offset: usize) {
-    let mut v = AlignedVec::new(0, n + n / 2 + offset);
+    // Aligned source, misaligned dest
+    let mut v = AlignedSlice::new(0, n + n / 2 + offset, 0);
     b.bytes = n as u64;
     b.iter(|| {
         let s: &mut [u8] = black_box(&mut v);
@@ -142,7 +110,8 @@ fn memmove_builtin(b: &mut Bencher, n: usize, offset: usize) {
 }
 
 fn memmove_rust(b: &mut Bencher, n: usize, offset: usize) {
-    let mut v = AlignedVec::new(0, n + n / 2 + offset);
+    // Aligned source, misaligned dest
+    let mut v = AlignedSlice::new(0, n + n / 2 + offset, 0);
     b.bytes = n as u64;
     b.iter(|| {
         let dst: *mut u8 = black_box(&mut v[n / 2 + offset..]).as_mut_ptr();