https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82918
--- Comment #2 from Antony Polukhin <antoshkka at gmail dot com> ---
The example from above now produces optimal assembly on GCC-9 (trunk).
However, swapping first two lines still produces suboptimal result:
struct array {
int data[3];
};
void foo2(array& value, const array& value2) {
if (&value == &value2) return;
value.data[1] = value2.data[0];
value.data[0] = value2.data[0];
value.data[2] = value2.data[0];
}
Outputs:
_Z4foo2R5arrayRKS_:
cmp rdi, rsi
je .L1
mov eax, DWORD PTR [rsi]
mov DWORD PTR [rdi+4], eax
mov DWORD PTR [rdi], eax
mov eax, DWORD PTR [rsi] <=== This is not required
mov DWORD PTR [rdi+8], eax
.L1:
ret
