/* Structure used to record preferences of given pseudo. */
struct reg_pref
{
- /* (enum reg_class) prefclass is the preferred class. */
+ /* (enum reg_class) prefclass is the preferred class. May be
+ NO_REGS if no class is better than memory. */
char prefclass;
/* altclass is a register class that we should use for allocating
best = reg_class_subunion[(int) best][class];
}
+ /* If no register class is better than memory, use memory. */
+ if (p->mem_cost < best_cost)
+ best = NO_REGS;
+
/* Record the alternate register class; i.e., a class for which
every register in it is better than using memory. If adding a
class would make a smaller class (i.e., no union of just those
to what we would add if this register were not in the
appropriate class. */
- if (reg_pref)
+ if (reg_pref && reg_pref[REGNO (op)].prefclass != NO_REGS)
alt_cost
+= (may_move_in_cost[mode]
[(unsigned char) reg_pref[REGNO (op)].prefclass]
to what we would add if this register were not in the
appropriate class. */
- if (reg_pref)
+ if (reg_pref && reg_pref[REGNO (op)].prefclass != NO_REGS)
alt_cost
+= (may_move_in_cost[mode]
[(unsigned char) reg_pref[REGNO (op)].prefclass]
int class;
unsigned int nr;
- if (regno >= FIRST_PSEUDO_REGISTER && reg_pref != 0)
+ if (regno >= FIRST_PSEUDO_REGISTER && reg_pref != 0
+ && reg_pref[regno].prefclass != NO_REGS)
{
enum reg_class pref = reg_pref[regno].prefclass;