LLVM error: "Instruction does not dominate all uses!" on Windows

[kryptan]

Code

Project is here: https://github.com/kryptan/llvm-error

Compile with cargo test --release on Windows-MSVC (compilation on Linux works fine).

src/lib.rs:

use std::future::Future;
use std::sync::Arc;

pub async fn run() {
    foo(|| async { create() }).await;
    foo(|| async { create() }).await;
}

async fn foo<F>(create: impl Fn() -> F)
where
    F: Future<Output = Struct>,
{
    call_empty::<()>(create().await, "").await;
}

struct Struct {
    _vec: Vec<u8>,
    _arc: Arc<()>,
}

fn create() -> Struct {
    Struct {
        _vec: Vec::new(),
        _arc: Arc::new(()),
    }
}

async fn call_empty<R>(_: Struct, _: &str) {
    empty()
}

fn empty() {}

tests/test.rs:

use std::future::Future;

#[test]
fn test() {
    let _: Box<dyn Future<Output = ()>> = Box::new(llvm_eror::run());
}

Meta

I tried two versions of the compiler (LLVM 9 & LLVM 10):

rustc --version --verbose:

rustc 1.45.0-nightly (9310e3bd4 2020-05-21)
binary: rustc
commit-hash: 9310e3bd4f425f84fc27878ebf2bda1f30935a63
commit-date: 2020-05-21
host: x86_64-pc-windows-msvc
release: 1.45.0-nightly
LLVM version: 10.0

rustc --version --verbose:

rustc 1.45.0-nightly (a74d1862d 2020-05-14)
binary: rustc
commit-hash: a74d1862d4d87a56244958416fd05976c58ca1a8
commit-date: 2020-05-14
host: x86_64-pc-windows-msvc
release: 1.45.0-nightly
LLVM version: 9.0

Error output

Instruction does not dominate all uses!
  %117 = phi i8* [ %117, %111 ], [ %117, %105 ], [ %43, %60 ], [ %43, %58 ], [ %51, %56 ]
  %117 = phi i8* [ %117, %111 ], [ %117, %105 ], [ %43, %60 ], [ %43, %58 ], [ %51, %56 ]
Instruction does not dominate all uses!
  %117 = phi i8* [ %117, %111 ], [ %117, %105 ], [ %43, %60 ], [ %43, %58 ], [ %51, %56 ]
  %117 = phi i8* [ %117, %111 ], [ %117, %105 ], [ %43, %60 ], [ %43, %58 ], [ %51, %56 ]
Instruction does not dominate all uses!
  %228 = phi i8* [ %228, %222 ], [ %228, %216 ], [ %155, %171 ], [ %155, %169 ], [ %162, %167 ]
  %228 = phi i8* [ %228, %222 ], [ %228, %216 ], [ %155, %171 ], [ %155, %169 ], [ %162, %167 ]
Instruction does not dominate all uses!
  %228 = phi i8* [ %228, %222 ], [ %228, %216 ], [ %155, %171 ], [ %155, %169 ], [ %162, %167 ]
  %228 = phi i8* [ %228, %222 ], [ %228, %216 ], [ %155, %171 ], [ %155, %169 ], [ %162, %167 ]
in function _ZN97_$LT$core..future..from_generator..GenFuture$LT$T$GT$$u20$as$u20$core..future..future..Future$GT$4poll17hf4840ccb0415d3e1E
LLVM ERROR: Broken function found, compilation aborted!
error: could not compile `llvm_eror`.

[jonas-schievink]

Regression from rustc 1.45.0-nightly (bad3bf6 2020-05-09) to rustc 1.45.0-nightly (9912925 2020-05-10)

bad3bf6...9912925

Further bisection might be needed

[jonas-schievink]

A smaller reproduction would be useful (if that's possible), marking needs-mcve

[jonas-schievink]

@rustbot ping cleanup