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c16c22cc9c
The optimized clone method ends up as the following MIR:
```
_2 = copy ((*_1).0: i32);
_3 = copy ((*_1).1: u64);
_4 = copy ((*_1).2: [i8; 3]);
_0 = Foo { a: move _2, b: move _3, c: move _4 };
```
We can transform this to:
```
_0 = copy (*_1);
```
41 lines
812 B
Rust
41 lines
812 B
Rust
//@ revisions: DEBUGINFO NODEBUGINFO
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//@ compile-flags: -O -Cno-prepopulate-passes
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//@ [DEBUGINFO] compile-flags: -Cdebuginfo=full
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// From https://github.com/rust-lang/rust/issues/128081.
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// Ensure that we only generate a memcpy instruction.
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#![crate_type = "lib"]
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#[derive(Clone)]
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struct SubCloneAndCopy {
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v1: u32,
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v2: u32,
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}
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#[derive(Clone)]
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struct CloneOnly {
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v1: u8,
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v2: u8,
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v3: u8,
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v4: u8,
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v5: u8,
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v6: u8,
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v7: u8,
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v8: u8,
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v9: u8,
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v_sub: SubCloneAndCopy,
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v_large: [u8; 256],
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}
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// CHECK-LABEL: define {{.*}}@clone_only(
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#[no_mangle]
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pub fn clone_only(v: &CloneOnly) -> CloneOnly {
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// CHECK-NOT: call {{.*}}clone
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// CHECK-NOT: store i8
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// CHECK-NOT: store i32
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// CHECK: call void @llvm.memcpy
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// CHECK-NEXT: ret void
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v.clone()
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}
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