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// unit-test: GVN
// EMIT_MIR_FOR_EACH_PANIC_STRATEGY
#![feature(raw_ref_op)]
#![feature(rustc_attrs)]
#![allow(unconditional_panic)]
struct S<T>(T);
fn subexpression_elimination(x: u64, y: u64, mut z: u64) {
opaque(x + y);
opaque(x * y);
opaque(x - y);
opaque(x / y);
opaque(x % y);
opaque(x & y);
opaque(x | y);
opaque(x ^ y);
opaque(x << y);
opaque(x >> y);
opaque(x as u32);
opaque(x as f32);
opaque(S(x));
opaque(S(x).0);
// Those are duplicates to substitute somehow.
opaque((x + y) + z);
opaque((x * y) + z);
opaque((x - y) + z);
opaque((x / y) + z);
opaque((x % y) + z);
opaque((x & y) + z);
opaque((x | y) + z);
opaque((x ^ y) + z);
opaque((x << y) + z);
opaque((x >> y) + z);
opaque(S(x));
opaque(S(x).0);
// We can substitute through an immutable reference too.
let a = &z;
opaque(*a + x);
opaque(*a + x);
// But not through a mutable reference or a pointer.
let b = &mut z;
opaque(*b + x);
opaque(*b + x);
unsafe {
let c = &raw const z;
opaque(*c + x);
opaque(*c + x);
let d = &raw mut z;
opaque(*d + x);
opaque(*d + x);
}
// We can substitute again, but not with the earlier computations.
// Important: `e` is not `a`!
let e = &z;
opaque(*e + x);
opaque(*e + x);
}
fn wrap_unwrap<T: Copy>(x: T) -> T {
match Some(x) {
Some(y) => y,
None => panic!(),
}
}
fn repeated_index<T: Copy, const N: usize>(x: T, idx: usize) {
let a = [x; N];
opaque(a[0]);
opaque(a[idx]);
}
fn arithmetic(x: u64) {
opaque(x + 0);
opaque(x - 0);
opaque(x * 0);
opaque(x * 1);
opaque(x / 0);
opaque(x / 1);
opaque(0 / x);
opaque(1 / x);
opaque(x % 0);
opaque(x % 1);
opaque(0 % x);
opaque(1 % x);
opaque(x & 0);
opaque(x | 0);
opaque(x ^ 0);
opaque(x >> 0);
opaque(x << 0);
}
#[rustc_inherit_overflow_checks]
fn arithmetic_checked(x: u64) {
opaque(x + 0);
opaque(x - 0);
opaque(x * 0);
opaque(x * 1);
opaque(x / 0);
opaque(x / 1);
opaque(0 / x);
opaque(1 / x);
opaque(x % 0);
opaque(x % 1);
opaque(0 % x);
opaque(1 % x);
opaque(x & 0);
opaque(x | 0);
opaque(x ^ 0);
opaque(x >> 0);
opaque(x << 0);
}
fn arithmetic_float(x: f64) {
opaque(x + 0.);
opaque(x - 0.);
opaque(x * 0.);
opaque(x / 0.);
opaque(0. / x);
opaque(x % 0.);
opaque(0. % x);
// Those are not simplifiable to `true`/`false`, thanks to NaNs.
opaque(x == x);
opaque(x != x);
}
fn cast() {
let i = 1_i64;
let u = 1_u64;
let f = 1_f64;
opaque(i as u8);
opaque(i as u16);
opaque(i as u32);
opaque(i as u64);
opaque(i as i8);
opaque(i as i16);
opaque(i as i32);
opaque(i as i64);
opaque(i as f32);
opaque(i as f64);
opaque(u as u8);
opaque(u as u16);
opaque(u as u32);
opaque(u as u64);
opaque(u as i8);
opaque(u as i16);
opaque(u as i32);
opaque(u as i64);
opaque(u as f32);
opaque(u as f64);
opaque(f as u8);
opaque(f as u16);
opaque(f as u32);
opaque(f as u64);
opaque(f as i8);
opaque(f as i16);
opaque(f as i32);
opaque(f as i64);
opaque(f as f32);
opaque(f as f64);
}
fn multiple_branches(t: bool, x: u8, y: u8) {
if t {
opaque(x + y); // a
opaque(x + y); // should reuse a
} else {
opaque(x + y); // b
opaque(x + y); // shoud reuse b
}
opaque(x + y); // c
if t {
opaque(x + y); // should reuse c
} else {
opaque(x + y); // should reuse c
}
}
fn references(mut x: impl Sized) {
opaque(&x);
opaque(&x); // should not reuse a
opaque(&mut x);
opaque(&mut x); // should not reuse a
opaque(&raw const x);
opaque(&raw const x); // should not reuse a
opaque(&raw mut x);
opaque(&raw mut x); // should not reuse a
}
fn dereferences(t: &mut u32, u: &impl Copy, s: &S<u32>) {
opaque(*t);
opaque(*t); // this cannot reuse a, as x is &mut.
let z = &raw const *t;
unsafe { opaque(*z) };
unsafe { opaque(*z) }; // this cannot reuse a, as x is *const.
let z = &raw mut *t;
unsafe { opaque(*z) };
unsafe { opaque(*z) }; // this cannot reuse a, as x is *mut.
let z = &*t;
opaque(*z);
opaque(*z); // this can reuse, as `z` is immutable ref, Freeze and Copy.
opaque(&*z); // but not for a reborrow.
opaque(*u);
opaque(*u); // this cannot reuse, as `z` is not Freeze.
opaque(s.0);
opaque(s.0); // *s is not Copy, by (*s).0 is, so we can reuse.
}
fn slices() {
let s = "my favourite slice"; // This is a `Const::Slice` in MIR.
opaque(s);
let t = s; // This should be the same pointer, so cannot be a `Const::Slice`.
opaque(t);
assert_eq!(s.as_ptr(), t.as_ptr());
let u = unsafe { std::mem::transmute::<&str, &[u8]>(s) };
opaque(u);
assert_eq!(s.as_ptr(), u.as_ptr());
}
fn main() {
subexpression_elimination(2, 4, 5);
wrap_unwrap(5);
repeated_index::<u32, 7>(5, 3);
arithmetic(5);
arithmetic_checked(5);
arithmetic_float(5.);
cast();
multiple_branches(true, 5, 9);
references(5);
dereferences(&mut 5, &6, &S(7));
slices();
}
#[inline(never)]
fn opaque(_: impl Sized) {}
// EMIT_MIR gvn.subexpression_elimination.GVN.diff
// EMIT_MIR gvn.wrap_unwrap.GVN.diff
// EMIT_MIR gvn.repeated_index.GVN.diff
// EMIT_MIR gvn.arithmetic.GVN.diff
// EMIT_MIR gvn.arithmetic_checked.GVN.diff
// EMIT_MIR gvn.arithmetic_float.GVN.diff
// EMIT_MIR gvn.cast.GVN.diff
// EMIT_MIR gvn.multiple_branches.GVN.diff
// EMIT_MIR gvn.references.GVN.diff
// EMIT_MIR gvn.dereferences.GVN.diff
// EMIT_MIR gvn.slices.GVN.diff
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