[LLVMdev] Possible missed optimization?

[Jakob Stoklund Olesen]

On Sep 4, 2010, at 9:54 AM, Borja Ferrer <borja.ferav at gmail.com> wrote:

> Producing the following asm code:
>     xor    r15, r13  ; xor top part
>     mov    r8, r14
>     xor    r8, r12   ; xor bottom part
>     movi    r14, 18
>     xor    r14, r8  ; xor bottom part with imm value
> 
> However it could have produced:
>     xor     r15, r13
>     xor     r14, r12
>     movi   r8, 18
>     xor     r14, r8

Only by commuting the xor operands. Have you marked xor as commutable? See the other targets for how to do that.