What the constraint "o" in and<mode>3 means on MIPS backend

[Segher Boessenkool]

On Thu, Jun 15, 2017 at 05:48:33PM +0800, Paul Hua wrote:
> in mips.c:
> ...
> 3261 (define_insn "*and<mode>3"
> 3262   [(set (match_operand:GPR 0 "register_operand" "=d,d,d,!u,d,d,d,!u,d")
> 3263         (and:GPR (match_operand:GPR 1 "nonimmediate_operand"
> "o,o,W,!u,d,d,d,0,d")
> 
>                                              ^
> 3264                  (match_operand:GPR 2 "and_operand"
> "Yb,Yh,Yw,Uean,K,Yx,Yw,!u,d")))]
> ...
> 
> I do not find "o" in constraints.md and gcc internal.
> what is the "o" means?

It's in the gccint manual, node "Simple Constraints" (it means
offsettable memory).


Segher