gistfile1.rs

#[crate_type="lib"];

pub struct Foo {
    x: uint,
    y: uint
}

#[inline(never)]
#[no_mangle]
pub fn foo(f: Foo) -> Foo {
    f
}

#[no_mangle]
pub fn bar(f: Foo) -> Foo {
    foo(f)
}

gistfile2.ll

; Function Attrs: noinline nounwind uwtable
define void @foo(%struct.Foo* noalias nocapture sret, { i64, %tydesc*, i8*, i8*, i8 }* nocapture readnone, %struct.Foo* nocapture readonly) unnamed_addr #1 {
"function top level":
  %3 = bitcast %struct.Foo* %2 to i8*
  %4 = bitcast %struct.Foo* %0 to i8*
  tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %4, i8* %3, i64 16, i32 8, i1 false)
  ret void
}

; Function Attrs: nounwind uwtable
define void @bar(%struct.Foo* noalias nocapture sret, { i64, %tydesc*, i8*, i8*, i8 }* nocapture readnone, %struct.Foo* nocapture readonly) unnamed_addr #2 {
"function top level":
  %__self = alloca %struct.Foo, align 8
  %3 = bitcast %struct.Foo* %2 to i8*
  %4 = bitcast %struct.Foo* %__self to i8*
  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %4, i8* %3, i64 16, i32 8, i1 false)
  call void @foo(%struct.Foo* sret %0, { i64, %tydesc*, i8*, i8*, i8 }* undef, %struct.Foo* %__self)
  ret void
}