74 lines
2.2 KiB
Rust
74 lines
2.2 KiB
Rust
// ignore-debug: the debug assertions get in the way
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// compile-flags: -O -Z merge-functions=disabled
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#![crate_type = "lib"]
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// Ensure that trivial casts of vec elements are O(1)
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pub struct Wrapper<T>(T);
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#[repr(C)]
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pub struct Foo {
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a: u64,
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b: u64,
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c: u64,
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d: u64,
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}
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// Going from an aggregate struct to another type currently requires Copy to
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// enable the TrustedRandomAccess specialization. Without it optimizations do not yet
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// reliably recognize the loops as noop for repr(C) or non-Copy structs.
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#[derive(Copy, Clone)]
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pub struct Bar {
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a: u64,
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b: u64,
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c: u64,
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d: u64,
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}
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// CHECK-LABEL: @vec_iterator_cast_primitive
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#[no_mangle]
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pub fn vec_iterator_cast_primitive(vec: Vec<i8>) -> Vec<u8> {
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// CHECK-NOT: loop
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// CHECK-NOT: call
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vec.into_iter().map(|e| e as u8).collect()
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}
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// CHECK-LABEL: @vec_iterator_cast_wrapper
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#[no_mangle]
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pub fn vec_iterator_cast_wrapper(vec: Vec<u8>) -> Vec<Wrapper<u8>> {
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// CHECK-NOT: loop
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// CHECK-NOT: call
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vec.into_iter().map(|e| Wrapper(e)).collect()
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}
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// CHECK-LABEL: @vec_iterator_cast_unwrap
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#[no_mangle]
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pub fn vec_iterator_cast_unwrap(vec: Vec<Wrapper<u8>>) -> Vec<u8> {
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// CHECK-NOT: loop
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// CHECK-NOT: call
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vec.into_iter().map(|e| e.0).collect()
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}
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// CHECK-LABEL: @vec_iterator_cast_aggregate
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#[no_mangle]
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pub fn vec_iterator_cast_aggregate(vec: Vec<[u64; 4]>) -> Vec<Foo> {
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// FIXME These checks should be the same as other functions.
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// CHECK-NOT: @__rust_alloc
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// CHECK-NOT: @__rust_alloc
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vec.into_iter().map(|e| unsafe { std::mem::transmute(e) }).collect()
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}
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// CHECK-LABEL: @vec_iterator_cast_deaggregate
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#[no_mangle]
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pub fn vec_iterator_cast_deaggregate(vec: Vec<Bar>) -> Vec<[u64; 4]> {
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// FIXME These checks should be the same as other functions.
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// CHECK-NOT: @__rust_alloc
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// CHECK-NOT: @__rust_alloc
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// Safety: For the purpose of this test we assume that Bar layout matches [u64; 4].
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// This currently is not guaranteed for repr(Rust) types, but it happens to work here and
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// the UCG may add additional guarantees for homogenous types in the future that would make this
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// correct.
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vec.into_iter().map(|e| unsafe { std::mem::transmute(e) }).collect()
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}
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