| //@ compile-flags: -Copt-level=3 | |
| #![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 | |
| // | |
| // Temporarily disabled in #68835 to fix a soundness hole. | |
| // | |
| // fn triangle_inc(n: u64) -> u64 { | |
| // let mut count = 0; | |
| // for j in 0 ..= n { | |
| // count += j; | |
| // } | |
| // count | |
| // } | |
| // | |
| // // COMMENTEDCHECK-LABEL: @check_triangle_inc | |
| // #[no_mangle] | |
| // pub fn check_triangle_inc() -> u64 { | |
| // // COMMENTEDCHECK: 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 500050000000 | |
| foo3r(10000) | |
| } |