Optimizing parameters in C function for MIPs/gcc -

i'm trying optimize code, , discovered gcc treats 2 uint_64 parameters differently struct 2 uint_64's in it. if have:

void testfn2parm( uint64_t p1, uint64_t p2 ) {     tp[0] = p1;     tp[1] = p2; } 

it resolves to:

void testfn2parm( uint64_t p1, uint64_t p2 ) { tp[0] = p1; 1d18:       3c020000        lui     v0,0x0 1d1c:       fc440000        sd      a0,0(v0) tp[1] = p2; 1d20:       64430000        daddiu  v1,v0,0 1d24:       03e00008        jr      ra 1d28:       fc650008        sd      a1,8(v1) 1d2c:       00000000        nop 

where a0 , a1 values of parameters -- no stack access. however, if do:

struct ts {      uint64_t    t64[2]; };  void testfntsparm( struct ts ts ) {     tp[0] = ts.t64[0];     tp[1] = ts.t64[1]; } 

which same thing, get:

void testfntsparm( struct ts ts ) { 1d88:       dc830008        ld      v1,8(a0) tp[0] = ts.t64[0]; 1d8c:       3c020000        lui     v0,0x0 1d90:       dc840000        ld      a0,0(a0) tp[1] = ts.t64[1]; 1d94:       64450000        daddiu  a1,v0,0 1d98:       fca30008        sd      v1,8(a1) 1d9c:       03e00008        jr      ra 1da0:       fc440000        sd      a0,0(v0) 1da4:       00000000        nop 

notice ld commands. in case a0 starts stack pointer. i'm wondering if there's clever ways around this, doesn't involve rewriting calling functions? (i'm using cross-compiler mips based on gcc 4.7)