[PATCH] D115955: [SLP]Alternate vectorization for cmp instructions.

[Mikael Holmén via Phabricator via llvm-commits]

uabelho added a comment.

In D115955#3322721 <https://reviews.llvm.org/D115955#3322721>, @ABataev wrote:

> In D115955#3322699 <https://reviews.llvm.org/D115955#3322699>, @uabelho wrote:
>
>> In D115955#3322693 <https://reviews.llvm.org/D115955#3322693>, @ABataev wrote:
>>
>>> In D115955#3322678 <https://reviews.llvm.org/D115955#3322678>, @uabelho wrote:
>>>
>>>> I think I'm seeing a miscompile with this patch on trunk. Are we aware of any such problems?
>>>
>>> Do you have a reproducer or something like this?
>>
>> Not yet. I'm trying to extract something but thought I'd ask if you're already aware of any miscompilation problems in the meantime.
>
> No.

Ok, here's a reproducer:

  opt --passes=slp-vectorizer slp.ll -o - -S

With this patch, the function returns the value 2. Without the patch the value returned is 0.
This can be seen with

  build-all/bin/opt --passes=slp-vectorizer slp.ll -o - -S | build-all/bin/opt -O3 -o - -S

with/without this patch.
F22116201: slp.ll <https://reviews.llvm.org/F22116201>


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D115955/new/

https://reviews.llvm.org/D115955