mirror of https://github.com/rust-lang/rust
35 lines
1.1 KiB
Rust
35 lines
1.1 KiB
Rust
//@ compile-flags: -C no-prepopulate-passes -O -Z mir-opt-level=3 -Zunsound-mir-opts
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// Ensure that `x?` has no overhead on `Result<T, E>` due to identity `match`es in lowering.
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// This requires inlining to trigger the MIR optimizations in `SimplifyArmIdentity`.
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#![crate_type = "lib"]
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type R = Result<u64, i32>;
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// This was written to the `?` from `try_trait`, but `try_trait_v2` uses a different structure,
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// so the relevant desugar is copied inline in order to keep the test testing the same thing.
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// FIXME(#85133): while this might be useful for `r#try!`, it would be nice to have a MIR
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// optimization that picks up the `?` desugaring, as `SimplifyArmIdentity` does not.
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#[no_mangle]
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pub fn try_identity(x: R) -> R {
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// CHECK: start:
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// FIXME(JakobDegen): Broken by deaggregation change CHECK-NOT\: br {{.*}}
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// CHECK ret void
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let y = match into_result(x) {
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Err(e) => return from_error(From::from(e)),
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Ok(v) => v,
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};
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Ok(y)
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}
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#[inline]
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fn into_result<T, E>(r: Result<T, E>) -> Result<T, E> {
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r
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}
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#[inline]
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fn from_error<T, E>(e: E) -> Result<T, E> {
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Err(e)
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}
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