From b858c591dd85f51bb515f492cfa8a0252339ddb9 Mon Sep 17 00:00:00 2001 From: Scott McMurray Date: Thu, 11 Jan 2024 21:20:15 -0800 Subject: [PATCH] Tune the inlinability of `Result::unwrap` --- library/core/src/result.rs | 2 +- tests/codegen/infallible-unwrap-in-opt-z.rs | 26 +++++++++++++++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) create mode 100644 tests/codegen/infallible-unwrap-in-opt-z.rs diff --git a/library/core/src/result.rs b/library/core/src/result.rs index eff1b9b59b14e..1f448984e531c 100644 --- a/library/core/src/result.rs +++ b/library/core/src/result.rs @@ -1061,7 +1061,7 @@ impl Result { /// let x: Result = Err("emergency failure"); /// x.unwrap(); // panics with `emergency failure` /// ``` - #[inline] + #[inline(always)] #[track_caller] #[stable(feature = "rust1", since = "1.0.0")] pub fn unwrap(self) -> T diff --git a/tests/codegen/infallible-unwrap-in-opt-z.rs b/tests/codegen/infallible-unwrap-in-opt-z.rs new file mode 100644 index 0000000000000..5c57b41532fbb --- /dev/null +++ b/tests/codegen/infallible-unwrap-in-opt-z.rs @@ -0,0 +1,26 @@ +// compile-flags: -C opt-level=z --edition=2021 +// ignore-debug + +#![crate_type = "lib"] + +// From + +// CHECK-LABEL: @read_up_to_8( +#[no_mangle] +pub fn read_up_to_8(buf: &[u8]) -> u64 { + // CHECK-NOT: unwrap_failed + if buf.len() < 4 { + // actual instance has more code. + return 0; + } + let lo = u32::from_le_bytes(buf[..4].try_into().unwrap()) as u64; + let hi = u32::from_le_bytes(buf[buf.len() - 4..][..4].try_into().unwrap()) as u64; + lo | (hi << 8 * (buf.len() as u64 - 4)) +} + +// CHECK-LABEL: @checking_unwrap_expectation( +#[no_mangle] +pub fn checking_unwrap_expectation(buf: &[u8]) -> &[u8; 4] { + // CHECK: call void @_ZN4core6result13unwrap_failed17h + buf.try_into().unwrap() +}