[aarch64-port-dev ] [aarch64-port-dev] [10] RFR: 8184049 : Matching rule for ubfiz

[Felix Yang]

Hi,

    As I mentioned in
http://mail.openjdk.java.net/pipermail/aarch64-port-dev/2017-August/004767.html,
your modification looks good to me.
    I posted the GCC's way of doing the matching condition check just for a
reference.  As I see it, your modification is equal in functionality.

Thanks,
Felix

On 23 August 2017 at 20:12, Daniel Stewart <daniel.stewart at linaro.org>
wrote:

> Felix,
>
> I'm not sure I understand the check here and exactly what you are
> proposing. It appears to me that this check is for an arithmetic right
> shift, not a left shift, which is what we have my proposed solution. I
> could be wrong as I am not familiar with GCC, but I can't make sense of the
> check if the shift is a left shift. (Perhaps GCC is using the shift value
> as if it were encoded for a ubfm instruction?) Could you explain a bit more
> about what exactly you'd like to see?
>
> Thanks,
> Daniel
>
> On Tue, Aug 1, 2017 at 11:10 AM, Felix Yang <felix.yang at linaro.org> wrote:
>
>> LGTM, but I am not an official reviewer.
>>
>> Here is how the latest GCC compiler do the check, which is more readable
>> to me:
>>
>> /* Return true if the mask and a shift amount from an RTX of the form
>>    (x << SHFT_AMNT) & MASK are valid to combine into a UBFIZ instruction
>> of
>>    mode MODE.  See the *andim_ashift<mode>_bfiz pattern.  */
>>
>> bool
>> aarch64_mask_and_shift_for_ubfiz_p (machine_mode mode, rtx mask, rtx
>> shft_amnt)
>> {
>>   return CONST_INT_P (mask) && CONST_INT_P (shft_amnt)
>> && INTVAL (shft_amnt) < GET_MODE_BITSIZE (mode)
>> && exact_log2 ((INTVAL (mask) >> INTVAL (shft_amnt)) + 1) >= 0
>> && (INTVAL (mask) & ((1 << INTVAL (shft_amnt)) - 1)) == 0;
>> }
>>
>> Thanks,
>> Felix
>>
>> On 31 July 2017 at 20:22, Daniel Stewart <daniel.stewart at linaro.org>
>> wrote:
>>
>>> Updated webrev to address Felix's issue regarding the format.
>>>
>>> Please review and let me know of any changes/fixes.
>>>
>>> http://cr.openjdk.java.net/~njian/8184049/webrev.02/
>>>
>>> Daniel
>>>
>>> On Fri, Jul 28, 2017 at 1:37 PM, Andrew Haley <aph at redhat.com> wrote:
>>>
>>>> On 27/07/17 21:49, Daniel Stewart wrote:
>>>> > public void run(String [] args) {
>>>> >         long sum = this.sum | (1 << 27);
>>>> >         int n = (int)sum;
>>>> >         n = xorshift32(n);
>>>> >         for (int i = 0; i < 1000; i++) {
>>>> >             //System.out.println((int)Math.random());
>>>> >             n += testI(n);
>>>> >             n += testI2(n);
>>>> >             n += testI3(n);
>>>> >             n += testI4(n);
>>>> >             n += testI5(n);
>>>> >         }
>>>> >         long n1 = (long)n;
>>>> >         for (int i = 0; i < 1000; i++) {
>>>> >             n1 += testL(n1);
>>>> >             n1 += testL2(n1);
>>>> >             n1 += testL3(n1);
>>>> >             n1 += testL4(n1);
>>>> >             n1 += testConv(n1);
>>>> >         }
>>>> >         short n2 = (short)n;
>>>> >         for (int i = 0; i < 1000; i++) {
>>>> >             n2 += testConv2((short)n2);
>>>> >         }
>>>> >         n1 += n2;
>>>> >         for (int i = 0; i< 1000; i++) {
>>>> >             n1 += testConv3(n);
>>>>
>>>> This loop doesn't test the intrinsic.  I added
>>>>
>>>>                n = xorshift32(n);
>>>>
>>>> here.
>>>>
>>>> >         }
>>>> >         this.sum += sum ^ n1;
>>>>
>>>>
>>>> --
>>>> Andrew Haley
>>>> Java Platform Lead Engineer
>>>> Red Hat UK Ltd. <https://www.redhat.com>
>>>> EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671
>>>>
>>>
>>>
>>>
>>> --
>>> Daniel Stewart
>>>
>>
>>
>
>
> --
> Daniel Stewart
>