-/* Return an estimate of the cost of computing rtx X.
- One use is in cse, to decide which expression to keep in the hash table.
- Another is in rtl generation, to pick the cheapest way to multiply.
- Other uses like the latter are expected in the future. */
-
-int
-rtx_cost (rtx x, enum rtx_code outer_code ATTRIBUTE_UNUSED)
-{
- int i, j;
- enum rtx_code code;
- const char *fmt;
- int total;
-
- if (x == 0)
- return 0;
-
- /* Compute the default costs of certain things.
- Note that targetm.rtx_costs can override the defaults. */
-
- code = GET_CODE (x);
- switch (code)
- {
- case MULT:
- total = COSTS_N_INSNS (5);
- break;
- case DIV:
- case UDIV:
- case MOD:
- case UMOD:
- total = COSTS_N_INSNS (7);
- break;
- case USE:
- /* Used in loop.c and combine.c as a marker. */
- total = 0;
- break;
- default:
- total = COSTS_N_INSNS (1);
- }
-
- switch (code)
- {
- case REG:
- return 0;
-
- case SUBREG:
- /* If we can't tie these modes, make this expensive. The larger
- the mode, the more expensive it is. */
- if (! MODES_TIEABLE_P (GET_MODE (x), GET_MODE (SUBREG_REG (x))))
- return COSTS_N_INSNS (2
- + GET_MODE_SIZE (GET_MODE (x)) / UNITS_PER_WORD);
- break;
-
- default:
- if ((*targetm.rtx_costs) (x, code, outer_code, &total))
- return total;
- break;
- }
-
- /* Sum the costs of the sub-rtx's, plus cost of this operation,
- which is already in total. */
-
- fmt = GET_RTX_FORMAT (code);
- for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
- if (fmt[i] == 'e')
- total += rtx_cost (XEXP (x, i), code);
- else if (fmt[i] == 'E')
- for (j = 0; j < XVECLEN (x, i); j++)
- total += rtx_cost (XVECEXP (x, i, j), code);
-
- return total;
-}
-\f
-/* Return cost of address expression X.
- Expect that X is properly formed address reference. */
-
-int
-address_cost (rtx x, enum machine_mode mode)
-{
- /* The address_cost target hook does not deal with ADDRESSOF nodes. But,
- during CSE, such nodes are present. Using an ADDRESSOF node which
- refers to the address of a REG is a good thing because we can then
- turn (MEM (ADDRESSSOF (REG))) into just plain REG. */
-
- if (GET_CODE (x) == ADDRESSOF && REG_P (XEXP ((x), 0)))
- return -1;
-
- /* We may be asked for cost of various unusual addresses, such as operands
- of push instruction. It is not worthwhile to complicate writing
- of the target hook by such cases. */
-
- if (!memory_address_p (mode, x))
- return 1000;
-
- return (*targetm.address_cost) (x);
-}
-
-/* If the target doesn't override, compute the cost as with arithmetic. */
-
-int
-default_address_cost (rtx x)
-{
- return rtx_cost (x, MEM);
-}
OSDN Git Service
