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