Hi All, We are porting the gcc 4.8.1 to the new target and which has the pair 16 bit registers like AB or CD or EF and we modeled it in reg_class as AB,CD and DE 16 bit pair_regs and CD ,EF as 16 bit base_regs and A,B,C,D E and F as 8 bit as general_regs.
We are stuck with below issues like 1)How do we modelled such that the register alloc to pick the respective base_regs i.e CD,DE instead of AB as show in the below case LD AB ,_a; //invalid instead of it should be emit LD CD ,_a LD (AB),#100; // invalid instead of it should be emit LD (CD),#100 Please note that we override the target hook like REGNO_REG_CLASS ,but still no luck here . 2)Current target enforce the restrictions on the pair register set usage for multiplication like MUL A,B or MUL C,D or MUL E,F But not MUL A,C or MUL B,C etc not across the pair_regs . Anyone can please shed some lights here ,will be appreciate and help us in the great way . Thank you for the patience ~Umesh
