[RFC] type promotion pass

[Kugan Vivekanandarajah]

Hi Steve,

On 19 September 2017 at 05:45, Steve Ellcey <sellcey@cavium.com> wrote:
> On Mon, 2017-09-18 at 23:29 +0530, Prathamesh Kulkarni wrote:
>>
>> Hi Steve,
>> The patch is currently based on r249469. I will rebase it on ToT and
>> look into the build failure.
>> Thanks for pointing it out.
>>
>> Regards,
>> Prathamesh
>
> OK, I applied it to that version successfully.  The thing I wanted to
> check was to see if this helped with PR target/77729.  It does not,
> so I think even with this patch we would need my patch to address the
> issue of having GCC recognize that ldrb/ldhb zero out the top of a
> register and thus we do not need to mask it out later.
>
> https://gcc.gnu.org/ml/gcc-patches/2017-09/msg00929.html

I tried the testases you have in the patch with type promotion. Looks
like forwprop is reversing the promotion there. I haven't looked in
detail yet but -fno-tree-forwprop seems to remove 6 "and" from the
test case. I have a slightly different version to what Prathamseh has
posted and hope that there isn't any difference here.

Thanks,
Kugan