1 // compile-flags: -C opt-level=3
5 // #71602 reported a simple array comparison just generating a loop.
6 // This was originally fixed by ensuring it generates a single bcmp,
7 // but we now generate it as a load+icmp instead. `is_zero_slice` was
8 // tweaked to still test the case of comparison against a slice,
9 // and `is_zero_array` tests the new array-specific behaviour.
10 // The optimization was then extended to short slice-to-array comparisons,
11 // so the first test here now has a long slice to still get the bcmp.
13 // CHECK-LABEL: @is_zero_slice_long
15 pub fn is_zero_slice_long(data: &[u8; 456]) -> bool {
16 // CHECK: %[[BCMP:.+]] = tail call i32 @{{bcmp|memcmp}}({{.+}})
17 // CHECK-NEXT: %[[EQ:.+]] = icmp eq i32 %[[BCMP]], 0
18 // CHECK-NEXT: ret i1 %[[EQ]]
22 // CHECK-LABEL: @is_zero_slice_short
24 pub fn is_zero_slice_short(data: &[u8; 4]) -> bool {
25 // CHECK: %[[LOAD:.+]] = load i32, {{i32\*|ptr}} %{{.+}}, align 1
26 // CHECK-NEXT: %[[EQ:.+]] = icmp eq i32 %[[LOAD]], 0
27 // CHECK-NEXT: ret i1 %[[EQ]]
31 // CHECK-LABEL: @is_zero_array
33 pub fn is_zero_array(data: &[u8; 4]) -> bool {
34 // CHECK: %[[LOAD:.+]] = load i32, {{i32\*|ptr}} %{{.+}}, align 1
35 // CHECK-NEXT: %[[EQ:.+]] = icmp eq i32 %[[LOAD]], 0
36 // CHECK-NEXT: ret i1 %[[EQ]]