[Bug c/46711] __builtin_choose_expr checks not chosen expression

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46711

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> 2010-11-29 
19:40:04 UTC ---
Try:
static inline unsigned long *
_param(struct pt_regs *regs, const int num) __attribute__((always_inline));
static inline unsigned long *
_param(struct pt_regs *regs, const int num)
{
    switch (num) {
    case 0: return &PARAM0(regs);
    case 1: return &PARAM1(regs);
    case 2: return &PARAM2(regs);
    case 3: return &PARAM3(regs);
    case 4: return &PARAM4(regs);
    case 5: return &PARAM5(regs);
    }

    /* should not happen */
    return NULL;
}

#define PARM(regs, num) *_param(regs, num)

This will provide something which is always optimized even at -O0.