| // skip-filecheck |
| // EMIT_MIR_FOR_EACH_PANIC_STRATEGY |
| // Check that CopyProp does not propagate an assignment to a function argument |
| // (doing so can break usages of the original argument value) |
| //@ unit-test: CopyProp |
| fn dummy(x: u8) -> u8 { |
| x |
| } |
| |
| // EMIT_MIR copy_propagation_arg.foo.CopyProp.diff |
| fn foo(mut x: u8) { |
| // calling `dummy` to make a use of `x` that copyprop cannot eliminate |
| x = dummy(x); // this will assign a local to `x` |
| } |
| |
| // EMIT_MIR copy_propagation_arg.bar.CopyProp.diff |
| fn bar(mut x: u8) { |
| dummy(x); |
| x = 5; |
| } |
| |
| // EMIT_MIR copy_propagation_arg.baz.CopyProp.diff |
| fn baz(mut x: i32) -> i32 { |
| // self-assignment to a function argument should be eliminated |
| x = x; |
| x |
| } |
| |
| // EMIT_MIR copy_propagation_arg.arg_src.CopyProp.diff |
| 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); |
| } |