| // compile-flags: -C opt-level=3 -Zmerge-functions=disabled |
| |
| #![crate_type = "lib"] |
| |
| // #71602 reported a simple array comparison just generating a loop. |
| // This was originally fixed by ensuring it generates a single bcmp, |
| // but we now generate it as a load+icmp instead. `is_zero_slice` was |
| // tweaked to still test the case of comparison against a slice, |
| // and `is_zero_array` tests the new array-specific behaviour. |
| // The optimization was then extended to short slice-to-array comparisons, |
| // so the first test here now has a long slice to still get the bcmp. |
| |
| // CHECK-LABEL: @is_zero_slice_long |
| #[no_mangle] |
| pub fn is_zero_slice_long(data: &[u8; 456]) -> bool { |
| // CHECK: %[[BCMP:.+]] = tail call i32 @{{bcmp|memcmp}}({{.+}}) |
| // CHECK-NEXT: %[[EQ:.+]] = icmp eq i32 %[[BCMP]], 0 |
| // CHECK-NEXT: ret i1 %[[EQ]] |
| &data[..] == [0; 456] |
| } |
| |
| // CHECK-LABEL: @is_zero_slice_short |
| #[no_mangle] |
| pub fn is_zero_slice_short(data: &[u8; 4]) -> bool { |
| // CHECK: %[[LOAD:.+]] = load i32, {{i32\*|ptr}} %{{.+}}, align 1 |
| // CHECK-NEXT: %[[EQ:.+]] = icmp eq i32 %[[LOAD]], 0 |
| // CHECK-NEXT: ret i1 %[[EQ]] |
| &data[..] == [0; 4] |
| } |
| |
| // CHECK-LABEL: @is_zero_array |
| #[no_mangle] |
| pub fn is_zero_array(data: &[u8; 4]) -> bool { |
| // CHECK: %[[LOAD:.+]] = load i32, {{i32\*|ptr}} %{{.+}}, align 1 |
| // CHECK-NEXT: %[[EQ:.+]] = icmp eq i32 %[[LOAD]], 0 |
| // CHECK-NEXT: ret i1 %[[EQ]] |
| *data == [0; 4] |
| } |
