|  | //@ only-64bit llvm appears to use stores instead of memset on 32bit | 
|  | //@ compile-flags: -C opt-level=3 -Z merge-functions=disabled | 
|  | //@ needs-deterministic-layouts | 
|  |  | 
|  | // The below two functions ensure that both `String::new()` and `"".to_string()` | 
|  | // produce the identical code. | 
|  |  | 
|  | #![crate_type = "lib"] | 
|  |  | 
|  | // CHECK-LABEL: define {{(dso_local )?}}void @string_new | 
|  | #[no_mangle] | 
|  | pub fn string_new() -> String { | 
|  | // CHECK-NOT: load i8 | 
|  | // CHECK: store i{{32|64}} | 
|  | // CHECK-NEXT: getelementptr | 
|  | // CHECK-NEXT: store ptr | 
|  | // CHECK-NEXT: getelementptr | 
|  | // CHECK-NEXT: store i{{32|64}} | 
|  | // CHECK-NEXT: ret void | 
|  | String::new() | 
|  | } | 
|  |  | 
|  | // CHECK-LABEL: define {{(dso_local )?}}void @empty_to_string | 
|  | #[no_mangle] | 
|  | pub fn empty_to_string() -> String { | 
|  | // CHECK-NOT: load i8 | 
|  | // CHECK: store i{{32|64}} | 
|  | // CHECK-NEXT: getelementptr | 
|  | // CHECK-NEXT: store ptr | 
|  | // CHECK-NEXT: getelementptr | 
|  | // CHECK-NEXT: store i{{32|64}} | 
|  | // CHECK-NEXT: ret void | 
|  | "".to_string() | 
|  | } | 
|  |  | 
|  | // The below two functions ensure that both `vec![]` and `vec![].clone()` | 
|  | // produce the identical code. | 
|  |  | 
|  | // CHECK-LABEL: @empty_vec | 
|  | #[no_mangle] | 
|  | pub fn empty_vec() -> Vec<u8> { | 
|  | // CHECK: store i{{32|64}} | 
|  | // CHECK-NOT: load i8 | 
|  | // CHECK-NEXT: getelementptr | 
|  | // CHECK-NEXT: store ptr | 
|  | // CHECK-NEXT: getelementptr | 
|  | // CHECK-NEXT: store i{{32|64}} | 
|  | // CHECK-NEXT: ret void | 
|  | vec![] | 
|  | } | 
|  |  | 
|  | // CHECK-LABEL: @empty_vec_clone | 
|  | #[no_mangle] | 
|  | pub fn empty_vec_clone() -> Vec<u8> { | 
|  | // CHECK: store i{{32|64}} | 
|  | // CHECK-NOT: load i8 | 
|  | // CHECK-NEXT: getelementptr | 
|  | // CHECK-NEXT: store ptr | 
|  | // CHECK-NEXT: getelementptr | 
|  | // CHECK-NEXT: store i{{32|64}} | 
|  | // CHECK-NEXT: ret void | 
|  | vec![].clone() | 
|  | } |