Auto merge of #33583 - luqmana:tri-bool-mir, r=arielb1

MIR: Don't generate 3-armed boolean switch from match.

Fixes #33540.

Snippet from issue:
```Rust
fn foo(x: bool, y: bool) -> u32 {
    match (x, y) {
         (false, _) => 0,
         (_, false) => 1,
         (true, true) => 2,
    }
}
```

Generated MIR:
```
fn foo(arg0: bool, arg1: bool) -> u32 {
    let var0: bool;                      // "x" in scope 1 at 3bbm.rs:17:8: 17:9
    let var1: bool;                      // "y" in scope 1 at 3bbm.rs:17:17: 17:18
    let mut tmp0: (bool, bool);
    let mut tmp1: bool;
    let mut tmp2: bool;
    let mut tmp3: (&'static str, &'static str, u32);
    let mut tmp4: &'static (&'static str, &'static str, u32);

    bb0: {
        var0 = arg0;                     // scope 1 at 3bbm.rs:17:8: 17:9
        var1 = arg1;                     // scope 1 at 3bbm.rs:17:17: 17:18
        tmp1 = var0;                     // scope 5 at 3bbm.rs:18:12: 18:13
        tmp2 = var1;                     // scope 6 at 3bbm.rs:18:15: 18:16
        tmp0 = (tmp1, tmp2);             // scope 4 at 3bbm.rs:18:11: 18:17
        if((tmp0.0: bool)) -> [true: bb4, false: bb1]; // scope 3 at 3bbm.rs:19:10: 19:15
    }

    bb1: {
        return = const 0u32;             // scope 10 at 3bbm.rs:19:23: 19:24
        goto -> bb7;                     // scope 3 at 3bbm.rs:18:5: 22:6
    }

    bb2: {
        return = const 1u32;             // scope 11 at 3bbm.rs:20:23: 20:24
        goto -> bb7;                     // scope 3 at 3bbm.rs:18:5: 22:6
    }

    bb3: {
        return = const 2u32;             // scope 12 at 3bbm.rs:21:25: 21:26
        goto -> bb7;                     // scope 3 at 3bbm.rs:18:5: 22:6
    }

    bb4: {
        if((tmp0.1: bool)) -> [true: bb5, false: bb2]; // scope 3 at 3bbm.rs:20:13: 20:18
    }

    bb5: {
        if((tmp0.0: bool)) -> [true: bb3, false: bb6]; // scope 3 at 3bbm.rs:21:10: 21:14
    }

    bb6: {
        tmp4 = promoted0;                // scope 3 at 3bbm.rs:18:5: 22:6
        core::panicking::panic(tmp4);    // scope 3 at 3bbm.rs:18:5: 22:6
    }

    bb7: {
        return;                          // scope 0 at 3bbm.rs:17:1: 23:2
    }
}
```

Not sure about this approach. I was also thinking maybe just a standalone pass?

cc @arielb1, @nagisa

0 files changed, 0 insertions, 0 deletions