diff --git a/library/core/src/slice/rotate.rs b/library/core/src/slice/rotate.rs index 3e88978b78105..5d5ee4c7b6240 100644 --- a/library/core/src/slice/rotate.rs +++ b/library/core/src/slice/rotate.rs @@ -10,6 +10,7 @@ type BufType = [usize; 32]; /// # Safety /// /// The specified range must be valid for reading and writing. +#[inline] pub(super) unsafe fn ptr_rotate(left: usize, mid: *mut T, right: usize) { if T::IS_ZST { return; @@ -43,6 +44,7 @@ pub(super) unsafe fn ptr_rotate(left: usize, mid: *mut T, right: usize) { /// # Safety /// /// The specified range must be valid for reading and writing. +#[inline] unsafe fn ptr_rotate_memmove(left: usize, mid: *mut T, right: usize) { // The `[T; 0]` here is to ensure this is appropriately aligned for T let mut rawarray = MaybeUninit::<(BufType, [T; 0])>::uninit(); @@ -114,6 +116,7 @@ unsafe fn ptr_rotate_memmove(left: usize, mid: *mut T, right: usize) { /// # Safety /// /// The specified range must be valid for reading and writing. +#[inline] unsafe fn ptr_rotate_gcd(left: usize, mid: *mut T, right: usize) { // Algorithm 2 // Microbenchmarks indicate that the average performance for random shifts is better all @@ -218,6 +221,7 @@ unsafe fn ptr_rotate_gcd(left: usize, mid: *mut T, right: usize) { /// # Safety /// /// The specified range must be valid for reading and writing. +#[inline] unsafe fn ptr_rotate_swap(mut left: usize, mut mid: *mut T, mut right: usize) { loop { if left >= right { diff --git a/tests/codegen/lib-optimizations/slice_rotate.rs b/tests/codegen/lib-optimizations/slice_rotate.rs new file mode 100644 index 0000000000000..d0a7b328d1845 --- /dev/null +++ b/tests/codegen/lib-optimizations/slice_rotate.rs @@ -0,0 +1,30 @@ +//@ compile-flags: -O + +#![crate_type = "lib"] + +// Ensure that the simple case of rotating by a constant 1 optimizes to the obvious thing + +// CHECK-LABEL: @rotate_left_by_one +#[no_mangle] +pub fn rotate_left_by_one(slice: &mut [i32]) { + // CHECK-NOT: phi + // CHECK-NOT: call + // CHECK-NOT: load + // CHECK-NOT: store + // CHECK-NOT: getelementptr + // CHECK: %[[END:.+]] = getelementptr + // CHECK-NEXT: %[[DIM:.+]] = getelementptr + // CHECK-NEXT: %[[LAST:.+]] = load + // CHECK-NEXT: %[[FIRST:.+]] = shl + // CHECK-NEXT: call void @llvm.memmove + // CHECK-NEXT: store i32 %[[LAST]], ptr %[[DIM:.+]] + // CHECK-NOT: phi + // CHECK-NOT: call + // CHECK-NOT: load + // CHECK-NOT: store + // CHECK-NOT: getelementptr + // CHECK: ret void + if !slice.is_empty() { + slice.rotate_left(1); + } +}