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https://github.com/rust-lang/rust.git
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Nikita Popov
463ad9098e
If LLVM 7 is used, generate memcpy/memmove with differing src/dst alignment. I've added new FFI functions to construct these through the builder API, which is more convenient than dealing with differing intrinsic signatures depending on the LLVM version.
51 lines
1.7 KiB
Rust
51 lines
1.7 KiB
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// compile-flags: -C no-prepopulate-passes
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// ignore-tidy-linelength
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// min-llvm-version 7.0
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#![crate_type = "lib"]
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pub struct Bytes {
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a: u8,
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b: u8,
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c: u8,
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d: u8,
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}
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// CHECK-LABEL: small_array_alignment
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// The array is stored as i32, but its alignment is lower, go with 1 byte to avoid target
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// dependent alignment
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#[no_mangle]
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pub fn small_array_alignment(x: &mut [i8; 4], y: [i8; 4]) {
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// CHECK: [[TMP:%.+]] = alloca i32
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// CHECK: %y = alloca [4 x i8]
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// CHECK: store i32 %0, i32* [[TMP]]
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// CHECK: [[Y8:%[0-9]+]] = bitcast [4 x i8]* %y to i8*
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// CHECK: [[TMP8:%[0-9]+]] = bitcast i32* [[TMP]] to i8*
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// CHECK: call void @llvm.memcpy.{{.*}}(i8* align 1 [[Y8]], i8* align 4 [[TMP8]], i{{[0-9]+}} 4, i1 false)
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*x = y;
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}
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// CHECK-LABEL: small_struct_alignment
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// The struct is stored as i32, but its alignment is lower, go with 1 byte to avoid target
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// dependent alignment
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#[no_mangle]
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pub fn small_struct_alignment(x: &mut Bytes, y: Bytes) {
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// CHECK: [[TMP:%.+]] = alloca i32
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// CHECK: %y = alloca %Bytes
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// CHECK: store i32 %0, i32* [[TMP]]
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// CHECK: [[Y8:%[0-9]+]] = bitcast %Bytes* %y to i8*
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// CHECK: [[TMP8:%[0-9]+]] = bitcast i32* [[TMP]] to i8*
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// CHECK: call void @llvm.memcpy.{{.*}}(i8* align 1 [[Y8]], i8* align 4 [[TMP8]], i{{[0-9]+}} 4, i1 false)
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*x = y;
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}
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