rust/tests/codegen/fatptr.rs

// compile-flags: -C no-prepopulate-passes

#![crate_type = "lib"]

pub trait T {}

// CHECK-LABEL: @copy_fat_ptr
#[no_mangle]
pub fn copy_fat_ptr(x: &T) {
// CHECK-NOT: extractvalue
    let x2 = x;
}
Avoid FCA loads and extractvalue when copying fat pointers Since fat pointers do not qualify as structural types, they got copied using load_ty and store_ty, which means that we load an FCA and use extractvalue to get the components of the fat pointer. This breaks certain optimizations in LLVM. Found via apasel422/ref_count#13 2015-11-20 20:42:13 +00:00			`// compile-flags: -C no-prepopulate-passes`

			`#![crate_type = "lib"]`

			`pub trait T {}`

			`// CHECK-LABEL: @copy_fat_ptr`
			`#[no_mangle]`
			`pub fn copy_fat_ptr(x: &T) {`
			`// CHECK-NOT: extractvalue`
			`let x2 = x;`
			`}`