Criterion benchmarks hang with target-cpu=znver1 #65618
Description
On my system, a Zen 1 AMD CPU, attempting to run Criterion benchmarks with RUSTFLAGS = "-C target-cpu=znver1" results in the benchmark hanging at the Analyzing stage for a few minutes before I killed the program.
Without the flags, it doesn't hang at all, as expected.
This affects stable, beta and nightly, and is probably related to LLVM 9.
Code that can hang on stable:
#[macro_use]
extern crate criterion;
use criterion::{Criterion, ParameterizedBenchmark};
fn criterion_benchmark(c: &mut Criterion) {
c.bench(
"bench",
ParameterizedBenchmark::new(
"old",
|b, _| {
b.iter(|| {});
},
vec![()],
)
.with_function("new", |b, _| {
b.iter(|| {});
}),
);
}
criterion_group!(my_benches, criterion_benchmark);
criterion_main!(my_benches);using cargo +stable bench
No special flags are present in the Cargo.toml
[package]
name = "bench-test"
version = "0.1.0"
authors = ["novacrazy <[email protected]>"]
edition = "2018"
[dev-dependencies]
criterion = "0.3.0"
[[bench]]
name = "benchmark_name"
harness = false