mirror of https://github.com/rust-lang/rust
79 lines
1.6 KiB
Rust
79 lines
1.6 KiB
Rust
// `SetDiscriminant` does not actually write anything if the chosen variant is the untagged variant
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// of a niche encoding. Verify that we do not thread over this case.
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//@ test-mir-pass: JumpThreading
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#![feature(custom_mir)]
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#![feature(core_intrinsics)]
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use std::intrinsics::mir::*;
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enum E<T> {
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A,
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B(T),
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}
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// EMIT_MIR set_no_discriminant.f.JumpThreading.diff
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#[custom_mir(dialect = "runtime")]
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pub fn f() -> usize {
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// CHECK-LABEL: fn f(
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// CHECK-NOT: goto
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// CHECK: switchInt(
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// CHECK-NOT: goto
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mir!(
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let a: isize;
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let e: E<char>;
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{
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e = E::A;
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SetDiscriminant(e, 1);
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a = Discriminant(e);
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match a {
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0 => bb0,
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_ => bb1,
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}
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}
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bb0 = {
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RET = 0;
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Return()
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}
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bb1 = {
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RET = 1;
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Return()
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}
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)
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}
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// EMIT_MIR set_no_discriminant.generic.JumpThreading.diff
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#[custom_mir(dialect = "runtime")]
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pub fn generic<T>() -> usize {
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// CHECK-LABEL: fn generic(
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// CHECK-NOT: goto
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// CHECK: switchInt(
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// CHECK-NOT: goto
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mir!(
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let a: isize;
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let e: E<T>;
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{
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e = E::A;
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SetDiscriminant(e, 1);
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a = Discriminant(e);
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match a {
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0 => bb0,
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_ => bb1,
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}
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}
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bb0 = {
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RET = 0;
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Return()
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}
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bb1 = {
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RET = 1;
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Return()
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}
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)
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}
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fn main() {
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assert_eq!(f(), 0);
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assert_eq!(generic::<char>(), 0);
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}
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