mirror of https://github.com/rust-lang/rust.git
144 lines
3.6 KiB
Rust
144 lines
3.6 KiB
Rust
//@ compile-flags: -C no-prepopulate-passes
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#![crate_type = "lib"]
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use std::mem::MaybeUninit;
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// CHECK-LABEL: @zero_sized_elem
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#[no_mangle]
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pub fn zero_sized_elem() {
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// CHECK-NOT: br label %repeat_loop_header{{.*}}
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// CHECK-NOT: call void @llvm.memset.p0
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let x = [(); 4];
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opaque(&x);
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}
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// CHECK-LABEL: @zero_len_array
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#[no_mangle]
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pub fn zero_len_array() {
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// CHECK-NOT: br label %repeat_loop_header{{.*}}
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// CHECK-NOT: call void @llvm.memset.p0
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let x = [4; 0];
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opaque(&x);
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}
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// CHECK-LABEL: @byte_array
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#[no_mangle]
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pub fn byte_array() {
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// CHECK: call void @llvm.memset.{{.+}}(ptr {{.*}}, i8 7, i{{[0-9]+}} 4
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// CHECK-NOT: br label %repeat_loop_header{{.*}}
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let x = [7u8; 4];
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opaque(&x);
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}
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#[allow(dead_code)]
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#[derive(Copy, Clone)]
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enum Init {
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Loop,
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Memset,
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}
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// CHECK-LABEL: @byte_enum_array
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#[no_mangle]
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pub fn byte_enum_array() {
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// CHECK: call void @llvm.memset.{{.+}}(ptr {{.*}}, i8 {{.*}}, i{{[0-9]+}} 4
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// CHECK-NOT: br label %repeat_loop_header{{.*}}
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let x = [Init::Memset; 4];
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opaque(&x);
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}
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// CHECK-LABEL: @zeroed_integer_array
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#[no_mangle]
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pub fn zeroed_integer_array() {
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// CHECK: call void @llvm.memset.{{.+}}(ptr {{.*}}, i8 0, i{{[0-9]+}} 16
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// CHECK-NOT: br label %repeat_loop_header{{.*}}
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let x = [0u32; 4];
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opaque(&x);
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}
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// CHECK-LABEL: @nonzero_integer_array
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#[no_mangle]
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pub fn nonzero_integer_array() {
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// CHECK: br label %repeat_loop_header{{.*}}
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// CHECK-NOT: call void @llvm.memset.p0
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let x = [0x1a_2b_3c_4d_u32; 4];
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opaque(&x);
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}
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const N: usize = 100;
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// CHECK-LABEL: @u16_init_one_bytes
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#[no_mangle]
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pub fn u16_init_one_bytes() -> [u16; N] {
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// CHECK-NOT: select
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// CHECK-NOT: br
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// CHECK-NOT: switch
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// CHECK-NOT: icmp
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// CHECK: call void @llvm.memset.p0
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[const { u16::from_be_bytes([1, 1]) }; N]
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}
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// CHECK-LABEL: @option_none_init
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#[no_mangle]
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pub fn option_none_init() -> [Option<u8>; N] {
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// CHECK-NOT: select
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// CHECK-NOT: br
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// CHECK-NOT: switch
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// CHECK-NOT: icmp
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// CHECK: call void @llvm.memset.p0
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[const { None }; N]
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}
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// If there is partial provenance or some bytes are initialized and some are not,
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// we can't really do better than initialize bytes or groups of bytes together.
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// CHECK-LABEL: @option_maybe_uninit_init
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#[no_mangle]
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pub fn option_maybe_uninit_init() -> [MaybeUninit<u16>; N] {
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// CHECK-NOT: select
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// CHECK: br label %repeat_loop_header{{.*}}
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// CHECK-NOT: switch
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// CHECK: icmp
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// CHECK-NOT: call void @llvm.memset.p0
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[const {
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let mut val: MaybeUninit<u16> = MaybeUninit::uninit();
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let ptr = val.as_mut_ptr() as *mut u8;
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unsafe {
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ptr.write(0);
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}
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val
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}; N]
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}
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#[repr(packed)]
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struct Packed {
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start: u8,
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ptr: &'static (),
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rest: u16,
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rest2: u8,
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}
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// If there is partial provenance or some bytes are initialized and some are not,
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// we can't really do better than initialize bytes or groups of bytes together.
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// CHECK-LABEL: @option_maybe_uninit_provenance
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#[no_mangle]
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pub fn option_maybe_uninit_provenance() -> [MaybeUninit<Packed>; N] {
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// CHECK-NOT: select
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// CHECK: br label %repeat_loop_header{{.*}}
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// CHECK-NOT: switch
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// CHECK: icmp
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// CHECK-NOT: call void @llvm.memset.p0
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[const {
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let mut val: MaybeUninit<Packed> = MaybeUninit::uninit();
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unsafe {
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let ptr = &raw mut (*val.as_mut_ptr()).ptr;
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static HAS_ADDR: () = ();
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ptr.write_unaligned(&HAS_ADDR);
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}
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val
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}; N]
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}
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// Use an opaque function to prevent rustc from removing useless drops.
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#[inline(never)]
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pub fn opaque(_: impl Sized) {}
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