60208a0517
Thanks to 98892 for the tests I brought in here, as it demonstrated that 3×usize is currently suboptimal.
140 lines
3.6 KiB
Rust
140 lines
3.6 KiB
Rust
// compile-flags: -O -Z merge-functions=disabled
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// only-x86_64
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// ignore-debug: the debug assertions get in the way
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#![crate_type = "lib"]
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use std::mem::swap;
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type RGB48 = [u16; 3];
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// CHECK-LABEL: @swap_rgb48_manually(
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#[no_mangle]
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pub fn swap_rgb48_manually(x: &mut RGB48, y: &mut RGB48) {
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// FIXME: See #115212 for why this has an alloca again
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// CHECK: alloca [3 x i16], align 2
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// CHECK: call void @llvm.memcpy.p0.p0.i64({{.+}}, i64 6, i1 false)
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// CHECK: call void @llvm.memcpy.p0.p0.i64({{.+}}, i64 6, i1 false)
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// CHECK: call void @llvm.memcpy.p0.p0.i64({{.+}}, i64 6, i1 false)
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let temp = *x;
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*x = *y;
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*y = temp;
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}
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// CHECK-LABEL: @swap_rgb48
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#[no_mangle]
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pub fn swap_rgb48(x: &mut RGB48, y: &mut RGB48) {
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// CHECK-NOT: alloca
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// Whether `i8` is the best for this is unclear, but
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// might as well record what's actually happening right now.
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// CHECK: load i8
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// CHECK: load i8
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// CHECK: store i8
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// CHECK: store i8
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swap(x, y)
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}
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type RGBA64 = [u16; 4];
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// CHECK-LABEL: @swap_rgba64
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#[no_mangle]
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pub fn swap_rgba64(x: &mut RGBA64, y: &mut RGBA64) {
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// CHECK-NOT: alloca
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// CHECK-DAG: %[[XVAL:.+]] = load i64, ptr %x, align 2
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// CHECK-DAG: %[[YVAL:.+]] = load i64, ptr %y, align 2
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// CHECK-DAG: store i64 %[[YVAL]], ptr %x, align 2
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// CHECK-DAG: store i64 %[[XVAL]], ptr %y, align 2
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swap(x, y)
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}
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// CHECK-LABEL: @swap_vecs
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#[no_mangle]
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pub fn swap_vecs(x: &mut Vec<u32>, y: &mut Vec<u32>) {
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// CHECK-NOT: alloca
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// There are plenty more loads and stores than just these,
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// but at least one sure better be 64-bit (for size or capacity).
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// CHECK: load i64
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// CHECK: load i64
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// CHECK: store i64
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// CHECK: store i64
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// CHECK: ret void
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swap(x, y)
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}
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// CHECK-LABEL: @swap_slices
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#[no_mangle]
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pub fn swap_slices<'a>(x: &mut &'a [u32], y: &mut &'a [u32]) {
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// CHECK-NOT: alloca
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// CHECK: load ptr
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// CHECK: load i64
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// CHECK: load ptr
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// CHECK: load i64
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// CHECK: store ptr
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// CHECK: store i64
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// CHECK: store ptr
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// CHECK: store i64
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swap(x, y)
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}
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// LLVM doesn't vectorize a loop over 3-byte elements,
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// so we chunk it down to bytes and loop over those instead.
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type RGB24 = [u8; 3];
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// CHECK-LABEL: @swap_rgb24_slices
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#[no_mangle]
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pub fn swap_rgb24_slices(x: &mut [RGB24], y: &mut [RGB24]) {
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// CHECK-NOT: alloca
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// CHECK: load <{{[0-9]+}} x i8>
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// CHECK: store <{{[0-9]+}} x i8>
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if x.len() == y.len() {
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x.swap_with_slice(y);
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}
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}
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// This one has a power-of-two size, so we iterate over it directly
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type RGBA32 = [u8; 4];
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// CHECK-LABEL: @swap_rgba32_slices
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#[no_mangle]
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pub fn swap_rgba32_slices(x: &mut [RGBA32], y: &mut [RGBA32]) {
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// CHECK-NOT: alloca
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// CHECK: load <{{[0-9]+}} x i32>
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// CHECK: store <{{[0-9]+}} x i32>
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if x.len() == y.len() {
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x.swap_with_slice(y);
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}
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}
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// Strings have a non-power-of-two size, but have pointer alignment,
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// so we swap usizes instead of dropping all the way down to bytes.
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const _: () = assert!(!std::mem::size_of::<String>().is_power_of_two());
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// CHECK-LABEL: @swap_string_slices
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#[no_mangle]
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pub fn swap_string_slices(x: &mut [String], y: &mut [String]) {
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// CHECK-NOT: alloca
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// CHECK: load <{{[0-9]+}} x i64>
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// CHECK: store <{{[0-9]+}} x i64>
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if x.len() == y.len() {
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x.swap_with_slice(y);
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}
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}
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#[repr(C, packed)]
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pub struct Packed {
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pub first: bool,
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pub second: usize,
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}
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// CHECK-LABEL: @swap_packed_structs
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#[no_mangle]
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pub fn swap_packed_structs(x: &mut Packed, y: &mut Packed) {
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// CHECK-NOT: alloca
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// CHECK: ret void
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swap(x, y)
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}
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