src/test/codegen/adjustments.rs

   1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // compile-flags: -C no-prepopulate-passes
  12
  13 #![crate_type = "lib"]
  14 #![feature(rustc_attrs)]
  15
  16 // Hack to get the correct size for the length part in slices
  17 // CHECK: @helper([[USIZE:i[0-9]+]])
  18 #[no_mangle]
  19 fn helper(_: usize) {
  20 }
  21
  22 // CHECK-LABEL: @no_op_slice_adjustment
  23 #[no_mangle]
  24 #[rustc_no_mir] // FIXME #27840 MIR has different codegen.
  25 pub fn no_op_slice_adjustment(x: &[u8]) -> &[u8] {
  26     // We used to generate an extra alloca and memcpy for the block's trailing expression value, so
  27     // check that we copy directly to the return value slot
  28 // CHECK: [[SRC:%[0-9]+]] = bitcast { i8*, [[USIZE]] }* %x to
  29 // CHECK: [[DST:%[0-9]+]] = bitcast { i8*, [[USIZE]] }* %sret_slot to i8*
  30 // CHECK: call void @llvm.memcpy.{{.*}}(i8* [[DST]], i8* [[SRC]],
  31     { x }
  32 }
  33
  34 // CHECK-LABEL: @no_op_slice_adjustment2
  35 #[no_mangle]
  36 pub fn no_op_slice_adjustment2(x: &[u8]) -> &[u8] {
  37     // We used to generate an extra alloca and memcpy for the function's return value, so check
  38     // that there's no memcpy (the slice is written to sret_slot element-wise)
  39 // CHECK-NOT: call void @llvm.memcpy.
  40     no_op_slice_adjustment(x)
  41 }