Re: [GCC][PATCH][Aarch64] Stop redundant zero-extension after UMOV when in DI mode

[Sam Tebbs <sam.tebbs@arm.com>]

On 07/31/2018 11:16 PM, James Greenhalgh wrote:
> On Thu, Jul 26, 2018 at 11:52:15AM -0500, Sam Tebbs wrote:
>
> <snip>
>
>>> Thanks for making the changes and adding more test cases. I do however
>>> see that you are only covering 2 out of 4 new
>>> *aarch64_get_lane_zero_extenddi<> patterns. The
>>> *aarch64_get_lane_zero_extendsi<> were already existing. I don't mind
>>> those tests. I would just ask you to add the other two new patterns
>>> as well. Also since the different versions of the instruction generate
>>> same instructions (like foo_16qi and foo_8qi both give out the same
>>> instruction), I would suggest using a -fdump-rtl-final (or any relevant
>>> rtl dump) with the dg-options and using a scan-rtl-dump to scan the
>>> pattern name. Something like:
>>> /* { dg-do compile } */
>>> /* { dg-options "-O3 -fdump-rtl-final" } */
>>> ...
>>> ...
>>> /* { dg-final { scan-rtl-dump "aarch64_get_lane_zero_extenddiv16qi"
>>> "final" } } */
>>>
>>> Thanks
>>> Sudi
>> Hi Sudi,
>>
>> Thanks again. Here's an update that adds 4 more tests, so all 8 patterns
>> generated are now tested for!
> This is OK for trunk, thanks for the patch (and thanks Sudi for the review!)
>
> Thanks,
> James

Thank you James! I'd appreciate it if someone could commit it as I don't 
have commit rights yet.

Sam

>
>> Below is the updated changelog
>>
>> gcc/
>> 2018-07-26  Sam Tebbs  <sam.tebbs@arm.com>
>>
>>           * config/aarch64/aarch64-simd.md
>>           (*aarch64_get_lane_zero_extendsi<mode>):
>>           Rename to...
>> (*aarch64_get_lane_zero_extend<GPI:mode><VDQQH:mode>): ... This.
>>           Use GPI iterator instead of SI mode.
>>
>> gcc/testsuite
>> 2018-07-26  Sam Tebbs  <sam.tebbs@arm.com>
>>
>>           * gcc.target/aarch64/extract_zero_extend.c: New file
>>