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// This attempts to mutate `a` via a pointer derived from `addr_of!(a)`. That is UB
// according to Miri. However, the decision to make this UB - and to allow
// rustc to rely on that fact for the purpose of optimizations - has not been
// finalized.
//
// As such, we include this test to ensure that copy prop does not rely on that
// fact. Specifically, if `addr_of!(a)` could not be used to modify a, it would
// be correct for CopyProp to replace all occurrences of `a` with `c` - but that
// would cause `f(true)` to output `false` instead of `true`.
#![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 {
mir!({
let a = c;
let p = core::ptr::addr_of!(a);
let p2 = core::ptr::addr_of_mut!(*p);
*p2 = false;
RET = c;
Return()
})
}
fn main() {
assert_eq!(true, f(true));
}
// EMIT_MIR mutate_through_pointer.f.CopyProp.diff
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