1 // compile-flags: -C no-prepopulate-passes
2 // min-llvm-version: 14.0
4 // Check that we use undef (and not zero) for uninitialized bytes in constants.
8 use std::mem::MaybeUninit;
10 pub struct PartiallyUninit {
12 y: MaybeUninit<[u8; 10]>
15 // CHECK: [[FULLY_UNINIT:@[0-9]+]] = private unnamed_addr constant <{ [10 x i8] }> undef
17 // CHECK: [[PARTIALLY_UNINIT:@[0-9]+]] = private unnamed_addr constant <{ [4 x i8], [12 x i8] }> <{ [4 x i8] c"\EF\BE\AD\DE", [12 x i8] undef }>, align 4
19 // This shouldn't contain undef, since it contains more chunks
20 // than the default value of uninit_const_chunk_threshold.
21 // CHECK: [[UNINIT_PADDING_HUGE:@[0-9]+]] = private unnamed_addr constant <{ [32768 x i8] }> <{ [32768 x i8] c"{{.+}}" }>, align 4
23 // CHECK: [[FULLY_UNINIT_HUGE:@[0-9]+]] = private unnamed_addr constant <{ [16384 x i8] }> undef
25 // CHECK-LABEL: @fully_uninit
27 pub const fn fully_uninit() -> MaybeUninit<[u8; 10]> {
28 const M: MaybeUninit<[u8; 10]> = MaybeUninit::uninit();
29 // CHECK: call void @llvm.memcpy.{{.+}}({{i8\*|ptr}} align 1 %{{[0-9]+}}, {{i8\*|ptr}} align 1 {{.*}}[[FULLY_UNINIT]]{{.*}}, i{{(32|64)}} 10, i1 false)
33 // CHECK-LABEL: @partially_uninit
35 pub const fn partially_uninit() -> PartiallyUninit {
36 const X: PartiallyUninit = PartiallyUninit { x: 0xdeadbeef, y: MaybeUninit::uninit() };
37 // CHECK: call void @llvm.memcpy.{{.+}}({{i8\*|ptr}} align 4 %{{[0-9]+}}, {{i8\*|ptr}} align 4 {{.*}}[[PARTIALLY_UNINIT]]{{.*}}, i{{(32|64)}} 16, i1 false)
41 // CHECK-LABEL: @uninit_padding_huge
43 pub const fn uninit_padding_huge() -> [(u32, u8); 4096] {
44 const X: [(u32, u8); 4096] = [(123, 45); 4096];
45 // CHECK: call void @llvm.memcpy.{{.+}}({{i8\*|ptr}} align 4 %{{[0-9]+}}, {{i8\*|ptr}} align 4 {{.*}}[[UNINIT_PADDING_HUGE]]{{.*}}, i{{(32|64)}} 32768, i1 false)
49 // CHECK-LABEL: @fully_uninit_huge
51 pub const fn fully_uninit_huge() -> MaybeUninit<[u32; 4096]> {
52 const F: MaybeUninit<[u32; 4096]> = MaybeUninit::uninit();
53 // CHECK: call void @llvm.memcpy.{{.+}}({{i8\*|ptr}} align 4 %{{[0-9]+}}, {{i8\*|ptr}} align 4 {{.*}}[[FULLY_UNINIT_HUGE]]{{.*}}, i{{(32|64)}} 16384, i1 false)