rust/tests/mir-opt/gvn_copy_aggregate.remove_storage_dead.GVN.diff
DianQK c16c22cc9c
Simplify the canonical clone method to copy
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);
```
2024-09-14 13:30:35 +08:00

55 lines
1.3 KiB
Diff

- // MIR for `remove_storage_dead` before GVN
+ // MIR for `remove_storage_dead` after GVN
fn remove_storage_dead(_1: fn() -> AlwaysSome<T>) -> AlwaysSome<T> {
debug f => _1;
let mut _0: AlwaysSome<T>;
let _2: T;
let mut _3: AlwaysSome<T>;
let mut _4: fn() -> AlwaysSome<T>;
let _5: T;
let mut _6: T;
let mut _7: isize;
let mut _8: isize;
scope 1 {
debug v => _2;
}
scope 2 {
debug v => _5;
}
bb0: {
StorageLive(_2);
- StorageLive(_3);
+ nop;
StorageLive(_4);
_4 = copy _1;
- _3 = move _4() -> [return: bb1, unwind unreachable];
+ _3 = copy _1() -> [return: bb1, unwind unreachable];
}
bb1: {
StorageDead(_4);
- StorageLive(_5);
- _5 = move ((_3 as Some).0: T);
- _2 = move _5;
- StorageDead(_5);
+ nop;
+ _5 = copy ((_3 as Some).0: T);
+ _2 = copy _5;
+ nop;
_7 = discriminant(_3);
- StorageDead(_3);
+ nop;
StorageLive(_6);
- _6 = move _2;
- _0 = AlwaysSome::<T>::Some(move _6);
+ _6 = copy _5;
+ _0 = copy _3;
StorageDead(_6);
StorageDead(_2);
return;
}
}