tests/mir-opt/const_prop/control_flow_simplification.rs

// EMIT_MIR_FOR_EACH_PANIC_STRATEGY
//@ test-mir-pass: GVN
//@ compile-flags: -Zmir-opt-level=1

trait NeedsDrop: Sized {
    const NEEDS: bool = std::mem::needs_drop::<Self>();
}

impl<This> NeedsDrop for This {}

// EMIT_MIR control_flow_simplification.hello.GVN.diff
// EMIT_MIR control_flow_simplification.hello.runtime-optimized.after.mir
fn hello<T>() {
    // CHECK-LABEL: fn hello(
    // CHECK: bb0:
    // CHECK-NEXT: return;
    if <bool>::NEEDS {
        panic!()
    }
}

pub fn main() {
    hello::<()>();
    hello::<Vec<()>>();
}