rust/tests/codegen/swap-small-types.rs
Scott McMurray 7d537106a1 Let codegen decide when to mem::swap with immediates
Making `libcore` decide this is silly; the backend has so much better information about when it's a good idea.

So introduce a new `typed_swap` intrinsic with a fallback body, but replace that implementation for immediates and scalar pairs.
2024-03-17 11:59:18 -07:00

136 lines
3.5 KiB
Rust

//@ compile-flags: -O -Z merge-functions=disabled
//@ only-x86_64
#![crate_type = "lib"]
use std::mem::swap;
type RGB48 = [u16; 3];
// CHECK-LABEL: @swap_rgb48_manually(
#[no_mangle]
pub fn swap_rgb48_manually(x: &mut RGB48, y: &mut RGB48) {
// FIXME: See #115212 for why this has an alloca again
// CHECK: alloca [3 x i16], align 2
// CHECK: call void @llvm.memcpy.p0.p0.i64({{.+}}, i64 6, i1 false)
// CHECK: call void @llvm.memcpy.p0.p0.i64({{.+}}, i64 6, i1 false)
// CHECK: call void @llvm.memcpy.p0.p0.i64({{.+}}, i64 6, i1 false)
let temp = *x;
*x = *y;
*y = temp;
}
// CHECK-LABEL: @swap_rgb48
#[no_mangle]
pub fn swap_rgb48(x: &mut RGB48, y: &mut RGB48) {
// CHECK-NOT: alloca
// Whether `i8` is the best for this is unclear, but
// might as well record what's actually happening right now.
// CHECK: load i8
// CHECK: load i8
// CHECK: store i8
// CHECK: store i8
swap(x, y)
}
type RGBA64 = [u16; 4];
// CHECK-LABEL: @swap_rgba64
#[no_mangle]
pub fn swap_rgba64(x: &mut RGBA64, y: &mut RGBA64) {
// CHECK-NOT: alloca
// CHECK-DAG: %[[XVAL:.+]] = load i64, ptr %x, align 2
// CHECK-DAG: %[[YVAL:.+]] = load i64, ptr %y, align 2
// CHECK-DAG: store i64 %[[YVAL]], ptr %x, align 2
// CHECK-DAG: store i64 %[[XVAL]], ptr %y, align 2
swap(x, y)
}
// CHECK-LABEL: @swap_vecs
#[no_mangle]
pub fn swap_vecs(x: &mut Vec<u32>, y: &mut Vec<u32>) {
// CHECK-NOT: alloca
// There are plenty more loads and stores than just these,
// but at least one sure better be 64-bit (for size or capacity).
// CHECK: load i64
// CHECK: load i64
// CHECK: store i64
// CHECK: store i64
// CHECK: ret void
swap(x, y)
}
// CHECK-LABEL: @swap_slices
#[no_mangle]
pub fn swap_slices<'a>(x: &mut &'a [u32], y: &mut &'a [u32]) {
// CHECK-NOT: alloca
// CHECK: load ptr
// CHECK: load i64
// CHECK: call void @llvm.memcpy.p0.p0.i64({{.+}}, i64 16, i1 false)
// CHECK: store ptr
// CHECK: store i64
swap(x, y)
}
// LLVM doesn't vectorize a loop over 3-byte elements,
// so we chunk it down to bytes and loop over those instead.
type RGB24 = [u8; 3];
// CHECK-LABEL: @swap_rgb24_slices
#[no_mangle]
pub fn swap_rgb24_slices(x: &mut [RGB24], y: &mut [RGB24]) {
// CHECK-NOT: alloca
// CHECK: load <{{[0-9]+}} x i8>
// CHECK: store <{{[0-9]+}} x i8>
if x.len() == y.len() {
x.swap_with_slice(y);
}
}
// This one has a power-of-two size, so we iterate over it directly
type RGBA32 = [u8; 4];
// CHECK-LABEL: @swap_rgba32_slices
#[no_mangle]
pub fn swap_rgba32_slices(x: &mut [RGBA32], y: &mut [RGBA32]) {
// CHECK-NOT: alloca
// CHECK: load <{{[0-9]+}} x i32>
// CHECK: store <{{[0-9]+}} x i32>
if x.len() == y.len() {
x.swap_with_slice(y);
}
}
// Strings have a non-power-of-two size, but have pointer alignment,
// so we swap usizes instead of dropping all the way down to bytes.
const _: () = assert!(!std::mem::size_of::<String>().is_power_of_two());
// CHECK-LABEL: @swap_string_slices
#[no_mangle]
pub fn swap_string_slices(x: &mut [String], y: &mut [String]) {
// CHECK-NOT: alloca
// CHECK: load <{{[0-9]+}} x i64>
// CHECK: store <{{[0-9]+}} x i64>
if x.len() == y.len() {
x.swap_with_slice(y);
}
}
#[repr(C, packed)]
pub struct Packed {
pub first: bool,
pub second: usize,
}
// CHECK-LABEL: @swap_packed_structs
#[no_mangle]
pub fn swap_packed_structs(x: &mut Packed, y: &mut Packed) {
// CHECK-NOT: alloca
// CHECK: ret void
swap(x, y)
}