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// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// compile-flags: -O
// min-llvm-version 6.0
#![crate_type = "lib"]
// verify that LLVM recognizes a loop involving 0..=n and will const-fold it.
//------------------------------------------------------------------------------
// Example from original issue #45222
fn foo2(n: u64) -> u64 {
let mut count = 0;
for _ in 0..n {
for j in (0..=n).rev() {
count += j;
}
}
count
}
// CHECK-LABEL: @check_foo2
#[no_mangle]
pub fn check_foo2() -> u64 {
// CHECK: ret i64 500005000000000
foo2(100000)
}
//------------------------------------------------------------------------------
// Simplified example of #45222
fn triangle_inc(n: u64) -> u64 {
let mut count = 0;
for j in 0 ..= n {
count += j;
}
count
}
// CHECK-LABEL: @check_triangle_inc
#[no_mangle]
pub fn check_triangle_inc() -> u64 {
// CHECK: ret i64 5000050000
triangle_inc(100000)
}
//------------------------------------------------------------------------------
// Demo in #48012
fn foo3r(n: u64) -> u64 {
let mut count = 0;
(0..n).for_each(|_| {
(0 ..= n).rev().for_each(|j| {
count += j;
})
});
count
}
// CHECK-LABEL: @check_foo3r
#[no_mangle]
pub fn check_foo3r() -> u64 {
// CHECK: ret i64 500005000000000
foo3r(100000)
}
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