non_dominate.rs

//@ test-mir-pass: CopyProp

#![feature(custom_mir, core_intrinsics)]
#![allow(unused_assignments)]
extern crate core;
use core::intrinsics::mir::*;

#[custom_mir(dialect = "analysis", phase = "post-cleanup")]
fn f(c: bool) -> bool {
    // CHECK-LABEL: fn f(
    // CHECK: bb2: {
    // CHECK: _2 = copy _3;
    // CHECK: bb3: {
    // CHECK: _0 = copy _2;
    mir! {
        let a: bool;
        let b: bool;
        {
            Goto(bb1)
        }
        bb1 = {
            b = c;
            match b { false => bb3, _ => bb2 }
        }
        // This assignment to `a` does not dominate the use in `bb3`.
        // It should not be replaced by `b`.
        bb2 = {
            a = b;
            c = false;
            Goto(bb1)
        }
        bb3 = {
            RET = a;
            Return()
        }
    }
}

fn main() {
    assert_eq!(true, f(true));
}

// EMIT_MIR non_dominate.f.CopyProp.diff