[PATCH] D109159: [amdgpu] Enable selection of `s_cselect_b64`.

[Piotr Sobczak via Phabricator via llvm-commits]

piotr added a comment.

In D109159#2986876 <https://reviews.llvm.org/D109159#2986876>, @hliao wrote:

> In D109159#2986862 <https://reviews.llvm.org/D109159#2986862>, @foad wrote:
>
>> Just for the record, see also this comment from D82370 <https://reviews.llvm.org/D82370>:
>>
>>> Additionally, remove pattern for selects with 64-bit
>>> inputs, which are rare, because handling them properly
>>> requires more thought.
>>
>> This reverted part of D81925 <https://reviews.llvm.org/D81925>, which originally added both 32- and 64-bit patterns.
>
> In fact, we found that 64-bit select is not rare, partially due to the use of 64-bit pointers (tend to be uniform in most cases.) This patch is developed to address that pending issue in D81925 <https://reviews.llvm.org/D81925>.

Thanks for working on this! 
The observation I made about 64-bit inputs being rare was based on graphics content. The changes I did in D81925 <https://reviews.llvm.org/D81925> in si-fix-sgpr-copies did not universally work for 64-bit selects, so I removed that part in D82370 <https://reviews.llvm.org/D82370>.


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https://reviews.llvm.org/D109159