rust/tests/mir-opt/simplify_locals_removes_unused_consts.rs

// skip-filecheck
// EMIT_MIR_FOR_EACH_PANIC_STRATEGY
//@ test-mir-pass: SimplifyLocals-before-const-prop
//@ compile-flags: -C overflow-checks=no

fn use_zst(_: ((), ())) {}

struct Temp {
    x: u8,
}

fn use_u8(_: u8) {}

// EMIT_MIR simplify_locals_removes_unused_consts.main.SimplifyLocals-before-const-prop.diff
fn main() {
    let ((), ()) = ((), ());
    use_zst(((), ()));

    use_u8((Temp { x: 40 }).x + 2);
}
Allow to run filecheck in mir-opt tests. 2023-10-16 17:36:39 +00:00			`// skip-filecheck`
properly mark tests that require panic=abort 2023-06-08 07:18:34 +00:00			`// EMIT_MIR_FOR_EACH_PANIC_STRATEGY`
mir-opt tests: rename unit-test -> test-mir-pass 2024-04-20 11:19:34 +00:00			`//@ test-mir-pass: SimplifyLocals-before-const-prop`
Improve SimplifyLocals pass so it can remove unused consts The `ConstProp` can cause many locals to be initialized to a constant value and then never read from. `ConstProp` can also evaluate ZSTs into constant values. Previously, many of these would be removed by other parts of the MIR optimization pipeline. However, evaluating ZSTs (especially `()`) into constant values defeated those parts of the optimizer and so in a2e3ed5c054b544df6ceeb9e612d39af819f4aae, I added a hack to `ConstProp` that skips evaluating ZSTs to avoid that regression. This commit changes `SimplifyLocals` so that it doesn't consider writes of const values to a local to be a use of that local. In doing so, `SimplifyLocals` is able to remove otherwise unused locals left behind by other optimization passes (`ConstProp` in particular). 2019-10-17 10:46:51 +00:00			`//@ compile-flags: -C overflow-checks=no`

Don't print leading zeros on hex dumps constants 2020-02-05 11:17:41 +00:00			`fn use_zst(_: ((), ())) {}`
Improve SimplifyLocals pass so it can remove unused consts The `ConstProp` can cause many locals to be initialized to a constant value and then never read from. `ConstProp` can also evaluate ZSTs into constant values. Previously, many of these would be removed by other parts of the MIR optimization pipeline. However, evaluating ZSTs (especially `()`) into constant values defeated those parts of the optimizer and so in a2e3ed5c054b544df6ceeb9e612d39af819f4aae, I added a hack to `ConstProp` that skips evaluating ZSTs to avoid that regression. This commit changes `SimplifyLocals` so that it doesn't consider writes of const values to a local to be a use of that local. In doing so, `SimplifyLocals` is able to remove otherwise unused locals left behind by other optimization passes (`ConstProp` in particular). 2019-10-17 10:46:51 +00:00
			`struct Temp {`
Don't print leading zeros on hex dumps constants 2020-02-05 11:17:41 +00:00			`x: u8,`
Improve SimplifyLocals pass so it can remove unused consts The `ConstProp` can cause many locals to be initialized to a constant value and then never read from. `ConstProp` can also evaluate ZSTs into constant values. Previously, many of these would be removed by other parts of the MIR optimization pipeline. However, evaluating ZSTs (especially `()`) into constant values defeated those parts of the optimizer and so in a2e3ed5c054b544df6ceeb9e612d39af819f4aae, I added a hack to `ConstProp` that skips evaluating ZSTs to avoid that regression. This commit changes `SimplifyLocals` so that it doesn't consider writes of const values to a local to be a use of that local. In doing so, `SimplifyLocals` is able to remove otherwise unused locals left behind by other optimization passes (`ConstProp` in particular). 2019-10-17 10:46:51 +00:00			`}`

Don't print leading zeros on hex dumps constants 2020-02-05 11:17:41 +00:00			`fn use_u8(_: u8) {}`
Improve SimplifyLocals pass so it can remove unused consts The `ConstProp` can cause many locals to be initialized to a constant value and then never read from. `ConstProp` can also evaluate ZSTs into constant values. Previously, many of these would be removed by other parts of the MIR optimization pipeline. However, evaluating ZSTs (especially `()`) into constant values defeated those parts of the optimizer and so in a2e3ed5c054b544df6ceeb9e612d39af819f4aae, I added a hack to `ConstProp` that skips evaluating ZSTs to avoid that regression. This commit changes `SimplifyLocals` so that it doesn't consider writes of const values to a local to be a use of that local. In doing so, `SimplifyLocals` is able to remove otherwise unused locals left behind by other optimization passes (`ConstProp` in particular). 2019-10-17 10:46:51 +00:00
Move SimplifyLocals before ConstProp. 2022-12-04 19:20:55 +00:00			`// EMIT_MIR simplify_locals_removes_unused_consts.main.SimplifyLocals-before-const-prop.diff`
Improve SimplifyLocals pass so it can remove unused consts The `ConstProp` can cause many locals to be initialized to a constant value and then never read from. `ConstProp` can also evaluate ZSTs into constant values. Previously, many of these would be removed by other parts of the MIR optimization pipeline. However, evaluating ZSTs (especially `()`) into constant values defeated those parts of the optimizer and so in a2e3ed5c054b544df6ceeb9e612d39af819f4aae, I added a hack to `ConstProp` that skips evaluating ZSTs to avoid that regression. This commit changes `SimplifyLocals` so that it doesn't consider writes of const values to a local to be a use of that local. In doing so, `SimplifyLocals` is able to remove otherwise unused locals left behind by other optimization passes (`ConstProp` in particular). 2019-10-17 10:46:51 +00:00			`fn main() {`
			`let ((), ()) = ((), ());`
			`use_zst(((), ()));`

Don't print leading zeros on hex dumps constants 2020-02-05 11:17:41 +00:00			`use_u8((Temp { x: 40 }).x + 2);`
Improve SimplifyLocals pass so it can remove unused consts The `ConstProp` can cause many locals to be initialized to a constant value and then never read from. `ConstProp` can also evaluate ZSTs into constant values. Previously, many of these would be removed by other parts of the MIR optimization pipeline. However, evaluating ZSTs (especially `()`) into constant values defeated those parts of the optimizer and so in a2e3ed5c054b544df6ceeb9e612d39af819f4aae, I added a hack to `ConstProp` that skips evaluating ZSTs to avoid that regression. This commit changes `SimplifyLocals` so that it doesn't consider writes of const values to a local to be a use of that local. In doing so, `SimplifyLocals` is able to remove otherwise unused locals left behind by other optimization passes (`ConstProp` in particular). 2019-10-17 10:46:51 +00:00			`}`