mirror of https://github.com/rust-lang/rust.git
39 lines
1.4 KiB
Rust
39 lines
1.4 KiB
Rust
// 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]
|
|
}
|