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//@ test-mir-pass: DataflowConstProp
//@ compile-flags: -Zdump-mir-exclude-alloc-bytes
// EMIT_MIR_FOR_EACH_BIT_WIDTH
#![feature(custom_mir, core_intrinsics, rustc_attrs)]
use std::intrinsics::mir::*;
#[derive(Copy, Clone)]
enum E {
V1(i32),
V2(i32),
}
// EMIT_MIR enum.simple.DataflowConstProp.diff
// CHECK-LABEL: fn simple(
fn simple() {
// CHECK: debug e => [[e:_.*]];
// CHECK: debug x => [[x:_.*]];
// CHECK: [[e]] = const E::V1(0_i32);
let e = E::V1(0);
// CHECK: switchInt(const 0_isize) -> [0: [[target_bb:bb.*]], 1: bb2, otherwise: bb1];
// CHECK: [[target_bb]]: {
// CHECK: [[x]] = const 0_i32;
let x = match e {
E::V1(x1) => x1,
E::V2(x2) => x2,
};
}
// EMIT_MIR enum.constant.DataflowConstProp.diff
// CHECK-LABEL: fn constant(
fn constant() {
// CHECK: debug e => [[e:_.*]];
// CHECK: debug x => [[x:_.*]];
const C: E = E::V1(0);
// CHECK: [[e]] = const constant::C;
let e = C;
// CHECK: switchInt(const 0_isize) -> [0: [[target_bb:bb.*]], 1: bb2, otherwise: bb1];
// CHECK: [[target_bb]]: {
// CHECK: [[x]] = const 0_i32;
let x = match e {
E::V1(x1) => x1,
E::V2(x2) => x2,
};
}
// EMIT_MIR enum.statics.DataflowConstProp.diff
// CHECK-LABEL: fn statics(
fn statics() {
// CHECK: debug e1 => [[e1:_.*]];
// CHECK: debug x1 => [[x1:_.*]];
// CHECK: debug e2 => [[e2:_.*]];
// CHECK: debug x2 => [[x2:_.*]];
static C: E = E::V1(0);
// CHECK: [[e1]] = const E::V1(0_i32);
let e1 = C;
// CHECK: switchInt(const 0_isize) -> [0: [[target_bb:bb.*]], 1: bb2, otherwise: bb1];
// CHECK: [[target_bb]]: {
// CHECK: [[x1]] = const 0_i32;
let x1 = match e1 {
E::V1(x11) => x11,
E::V2(x12) => x12,
};
static RC: &E = &E::V2(4);
// CHECK: [[t:_.*]] = const {alloc5: &&E};
// CHECK: [[e2]] = copy (*[[t]]);
let e2 = RC;
// CHECK: switchInt({{move _.*}}) -> {{.*}}
// FIXME: add checks for x2. Currently, their MIRs are not symmetric in the two
// switch branches.
// One is `_9 = &(*_12) and another is `_9 = _11`. It is different from what we can
// get by printing MIR directly. It is better to check if there are any bugs in the
// MIR passes around this stage.
let x2 = match e2 {
E::V1(x21) => x21,
E::V2(x22) => x22,
};
}
#[rustc_layout_scalar_valid_range_start(1)]
#[rustc_nonnull_optimization_guaranteed]
struct NonZeroUsize(usize);
// EMIT_MIR enum.mutate_discriminant.DataflowConstProp.diff
// CHECK-LABEL: fn mutate_discriminant(
#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
fn mutate_discriminant() -> u8 {
mir! {
let x: Option<NonZeroUsize>;
{
SetDiscriminant(x, 1);
// This assignment overwrites the niche in which the discriminant is stored.
place!(Field(Field(Variant(x, 1), 0), 0)) = 0_usize;
// So we cannot know the value of this discriminant.
// CHECK: [[a:_.*]] = discriminant({{_.*}});
let a = Discriminant(x);
// CHECK: switchInt(copy [[a]]) -> [0: {{bb.*}}, otherwise: {{bb.*}}];
match a {
0 => bb1,
_ => bad,
}
}
bb1 = {
RET = 1;
Return()
}
bad = {
RET = 2;
Unreachable()
}
}
}
// EMIT_MIR enum.multiple.DataflowConstProp.diff
// CHECK-LABEL: fn multiple(
fn multiple(x: bool, i: u8) {
// CHECK: debug x => [[x:_.*]];
// CHECK: debug e => [[e:_.*]];
// CHECK: debug x2 => [[x2:_.*]];
// CHECK: debug y => [[y:_.*]];
let e = if x {
// CHECK: [[e]] = Option::<u8>::Some(move {{_.*}});
Some(i)
} else {
// CHECK: [[e]] = Option::<u8>::None;
None
};
// The dataflow state must have:
// discriminant(e) => Top
// (e as Some).0 => Top
// CHECK: [[x2]] = const 0_u8;
// CHECK: [[some:_.*]] = copy (({{_.*}} as Some).0: u8)
// CHECK: [[x2]] = copy [[some]];
let x2 = match e {
Some(i) => i,
None => 0,
};
// Therefore, `x2` should be `Top` here, and no replacement shall happen.
// CHECK-NOT: [[y]] = const
// CHECK: [[y]] = copy [[x2]];
// CHECK-NOT: [[y]] = const
let y = x2;
}
fn main() {
simple();
constant();
statics();
mutate_discriminant();
multiple(false, 5);
}
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