On 08/12/2015 06:23 AM, Segher Boessenkool wrote:
> On Tue, Aug 11, 2015 at 06:11:30PM -0700, Richard Henderson wrote:
>> This allows testing for a mask without having to call GEN_INT.
>>
>> Cc: David Edelsohn <dje....@gmail.com>
>> ---
>> * config/rs6000/rs6000.c (rs6000_is_valid_mask_wide): Split out from...
>> (rs6000_is_valid_mask): ... here.
>> (rs6000_is_valid_and_mask_wide): Split out from...
>> (rs6000_is_valid_and_mask): ... here.
>
> I don't like these "_wide" names much.
It follows the existing practice within the backend.
> You could overload the shorter
> name, if you really think creating some garbage const_int's is too much
> overhead (it might well be if you use it a lot more in later patches).
At one stage in the development (before I became much leaner with the search
for rotate), it really really mattered.
>> -bool
>> -rs6000_is_valid_mask (rtx mask, int *b, int *e, machine_mode mode)
>> +static bool
>> +rs6000_is_valid_mask_wide (unsigned HOST_WIDE_INT val, int *b, int *e, int
>> n)
>
> But why change the mode parameter? The code was clearer before.
So that we don't have to look up GET_MODE_BITSIZE (mode).
>> +static bool
>> +rs6000_is_valid_and_mask_wide (unsigned HOST_WIDE_INT val, machine_mode
>> mode)
>> {
>> int nb, ne;
>>
>> - if (!rs6000_is_valid_mask (mask, &nb, &ne, mode))
>> - return false;
>> + switch (mode)
>> + {
>> + case DImode:
>> + if (!rs6000_is_valid_mask_wide (val, &nb, &ne, 64))
>> + return false;
>> + /* For DImode, we need a rldicl, rldicr, or a rlwinm with
>> + mask that does not wrap. */
>> + return (ne == 0 || nb == 63 || (nb < 32 && ne <= nb));
>>
>> - /* For DImode, we need a rldicl, rldicr, or a rlwinm with mask that
>> - does not wrap. */
>> - if (mode == DImode)
>> - return (ne == 0 || nb == 63 || (nb < 32 && ne <= nb));
>> + case SImode:
>> + if (!rs6000_is_valid_mask_wide (val, &nb, &ne, 32))
>> + return false;
>> + /* For SImode, rlwinm can do everything. */
>> + return (nb < 32 && ne < 32);
>>
>> - /* For SImode, rlwinm can do everything. */
>> - if (mode == SImode)
>> - return (nb < 32 && ne < 32);
>> + default:
>> + return false;
>> + }
>> +}
>>
>> - return false;
>
> You don't need any of these changes then, either.
True, not *needed* per-se, but if you look closer I'm combining conditionals.
I think the replacement here is clearer.
>> /* Otherwise, fill in the lowest "hole"; if we can do the result with
>> one insn, we can do the whole thing with two. */
>> - unsigned HOST_WIDE_INT val = INTVAL (c);
>> + unsigned HOST_WIDE_INT val = UINTVAL (c);
>
> Does it matter?
No.
r~
