mirror of
https://github.com/rust-lang/rust.git
synced 2025-10-31 13:04:42 +00:00
143f39362a
Today we're making LLVM do a bunch of extra work for every enum you match on, even trivial stuff like `Option<bool>`. Let's not.
38 lines
738 B
Rust
38 lines
738 B
Rust
//@ compile-flags: -O
|
|
#![crate_type = "lib"]
|
|
#![feature(core_intrinsics)]
|
|
|
|
use std::intrinsics::cold_path;
|
|
|
|
#[inline(never)]
|
|
#[no_mangle]
|
|
pub fn path_a() {
|
|
println!("path a");
|
|
}
|
|
|
|
#[inline(never)]
|
|
#[no_mangle]
|
|
pub fn path_b() {
|
|
println!("path b");
|
|
}
|
|
|
|
#[no_mangle]
|
|
pub fn test(x: Option<bool>) {
|
|
if let Some(_) = x {
|
|
path_a();
|
|
} else {
|
|
cold_path();
|
|
path_b();
|
|
}
|
|
|
|
// CHECK-LABEL: void @test(i8{{.+}}%x)
|
|
// CHECK: %[[IS_NONE:.+]] = icmp eq i8 %x, 2
|
|
// CHECK: br i1 %[[IS_NONE]], label %bb2, label %bb1, !prof ![[NUM:[0-9]+]]
|
|
// CHECK: bb1:
|
|
// CHECK: path_a
|
|
// CHECK: bb2:
|
|
// CHECK: path_b
|
|
}
|
|
|
|
// CHECK: ![[NUM]] = !{!"branch_weights", {{(!"expected", )?}}i32 1, i32 2000}
|