[PATCH] D114799: [SLP]Improve vectorization of cmp instructions sequences.

[Alexey Bataev via Phabricator via llvm-commits]

ABataev added a comment.

In D114799#3227965 <https://reviews.llvm.org/D114799#3227965>, @zhuhan0 wrote:

> In D114799#3226181 <https://reviews.llvm.org/D114799#3226181>, @ABataev wrote:
>
>> In D114799#3226154 <https://reviews.llvm.org/D114799#3226154>, @zhuhan0 wrote:
>>
>>> Hi, we observed ~9% increase in `SLP.NumVectorInstructions` on SPEC's 508.namd_r with this change, using llvm-test-suite. I noticed the number is not reported here. Curious did you also see the same result? We tested on an Intel Skylake.
>>
>> I ttied with -march=native on Skylake, but did not see wuch results.
>
> I see. `-march=native` is the difference. I can reproduce a no change on namd with that flag. However, the number of vector instructions decreased significantly compared with removing that flag, which I found counter-intuitive.
>
> With `-march=native`
>
> |                           | With this patch | Without this patch |
> | SLP.NumVectorInstructions | 4446            | 4446               |
> |
>
> Without `-march=native`
>
> |                           | With this patch | Without this patch |
> | SLP.NumVectorInstructions | 5939            | 5473               |
> |

Sorry,

In D114799#3227965 <https://reviews.llvm.org/D114799#3227965>, @zhuhan0 wrote:

> In D114799#3226181 <https://reviews.llvm.org/D114799#3226181>, @ABataev wrote:
>
>> In D114799#3226154 <https://reviews.llvm.org/D114799#3226154>, @zhuhan0 wrote:
>>
>>> Hi, we observed ~9% increase in `SLP.NumVectorInstructions` on SPEC's 508.namd_r with this change, using llvm-test-suite. I noticed the number is not reported here. Curious did you also see the same result? We tested on an Intel Skylake.
>>
>> I ttied with -march=native on Skylake, but did not see wuch results.
>
> I see. `-march=native` is the difference. I can reproduce a no change on namd with that flag. However, the number of vector instructions decreased significantly compared with removing that flag, which I found counter-intuitive.
>
> With `-march=native`
>
> |                           | With this patch | Without this patch |
> | SLP.NumVectorInstructions | 4446            | 4446               |
> |
>
> Without `-march=native`
>
> |                           | With this patch | Without this patch |
> | SLP.NumVectorInstructions | 5939            | 5473               |
> |

Sorry, the number of vector instructions decreased or increased?


Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D114799/new/

https://reviews.llvm.org/D114799