2016-04-28 13:41 GMT+03:00 Jakub Jelinek <ja...@redhat.com>:
> On Thu, Apr 28, 2016 at 01:36:30PM +0300, Ilya Enkovich wrote:
>> @@ -3145,11 +3168,25 @@ scalar_chain::compute_convert_gain ()
>> || GET_CODE (src) == IOR
>> || GET_CODE (src) == XOR
>> || GET_CODE (src) == AND)
>> - gain += ix86_cost->add;
>> + {
>> + gain += ix86_cost->add;
>> + if (CONST_INT_P (XEXP (src, 0)))
>> + gain -= scalar_chain::vector_const_cost (XEXP (src, 0));
>> + if (CONST_INT_P (XEXP (src, 1)))
>> + gain -= scalar_chain::vector_const_cost (XEXP (src, 1));
>> + }
>> else if (GET_CODE (src) == COMPARE)
>> {
>> /* Assume comparison cost is the same. */
>> }
>> + else if (GET_CODE (src) == CONST_INT)
>> + {
>> + if (REG_P (dst))
>> + gain += COSTS_N_INSNS (2);
>> + else if (MEM_P (dst))
>> + gain += 2 * ix86_cost->int_store[2] - ix86_cost->sse_store[1];
>> + gain -= scalar_chain::vector_const_cost (src);
>> + }
>> else
>> gcc_unreachable ();
>
> Where does the 2 come from? Is it that the STV pass right now supports only
> 2 * wordsize modes? Also, I don't think we should treat equally constants
> that fit into the 32-bit immediates and constants that don't, the latter,
> when movabsq needs to be used, are more costly.
This variant is for DImode going to split into two SImode. TImode chains
have own cost model.
Thanks,
Ilya
>
> Jakub
