| // Copyright 2017 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. |
| |
| // Check that CopyPropagation does not propagate an assignment to a function argument |
| // (doing so can break usages of the original argument value) |
| |
| fn dummy(x: u8) -> u8 { |
| x |
| } |
| |
| fn foo(mut x: u8) { |
| // calling `dummy` to make an use of `x` that copyprop cannot eliminate |
| x = dummy(x); // this will assign a local to `x` |
| } |
| |
| fn bar(mut x: u8) { |
| dummy(x); |
| x = 5; |
| } |
| |
| fn baz(mut x: i32) { |
| // self-assignment to a function argument should be eliminated |
| x = x; |
| } |
| |
| fn arg_src(mut x: i32) -> i32 { |
| let y = x; |
| x = 123; // Don't propagate this assignment to `y` |
| y |
| } |
| |
| fn main() { |
| // Make sure the function actually gets instantiated. |
| foo(0); |
| bar(0); |
| baz(0); |
| arg_src(0); |
| } |
| |
| // END RUST SOURCE |
| // START rustc.foo.CopyPropagation.before.mir |
| // bb0: { |
| // ... |
| // _3 = _1; |
| // _2 = const dummy(move _3) -> bb1; |
| // } |
| // bb1: { |
| // ... |
| // _1 = move _2; |
| // ... |
| // } |
| // END rustc.foo.CopyPropagation.before.mir |
| // START rustc.foo.CopyPropagation.after.mir |
| // bb0: { |
| // ... |
| // _3 = _1; |
| // _2 = const dummy(move _3) -> bb1; |
| // } |
| // bb1: { |
| // ... |
| // _1 = move _2; |
| // ... |
| // } |
| // END rustc.foo.CopyPropagation.after.mir |
| // START rustc.bar.CopyPropagation.before.mir |
| // bb0: { |
| // StorageLive(_3); |
| // _3 = _1; |
| // _2 = const dummy(move _3) -> bb1; |
| // } |
| // bb1: { |
| // StorageDead(_3); |
| // _1 = const 5u8; |
| // ... |
| // return; |
| // } |
| // END rustc.bar.CopyPropagation.before.mir |
| // START rustc.bar.CopyPropagation.after.mir |
| // bb0: { |
| // ... |
| // _3 = _1; |
| // _2 = const dummy(move _3) -> bb1; |
| // } |
| // bb1: { |
| // ... |
| // _1 = const 5u8; |
| // ... |
| // return; |
| // } |
| // END rustc.bar.CopyPropagation.after.mir |
| // START rustc.baz.CopyPropagation.before.mir |
| // bb0: { |
| // StorageLive(_2); |
| // _2 = _1; |
| // _1 = move _2; |
| // StorageDead(_2); |
| // ... |
| // return; |
| // } |
| // END rustc.baz.CopyPropagation.before.mir |
| // START rustc.baz.CopyPropagation.after.mir |
| // bb0: { |
| // ... |
| // _2 = _1; |
| // _1 = move _2; |
| // ... |
| // return; |
| // } |
| // END rustc.baz.CopyPropagation.after.mir |
| // START rustc.arg_src.CopyPropagation.before.mir |
| // bb0: { |
| // ... |
| // _2 = _1; |
| // ... |
| // _1 = const 123i32; |
| // ... |
| // _0 = _2; |
| // ... |
| // return; |
| // } |
| // END rustc.arg_src.CopyPropagation.before.mir |
| // START rustc.arg_src.CopyPropagation.after.mir |
| // bb0: { |
| // ... |
| // _2 = _1; |
| // ... |
| // _1 = const 123i32; |
| // ... |
| // _0 = _2; |
| // ... |
| // return; |
| // } |
| // END rustc.arg_src.CopyPropagation.after.mir |