[PATCH] D25881: [EarlyCSE] Optimize MemoryPhis and reduce memory clobber queries w/ MemorySSA

Geoff Berry via llvm-commits llvm-commits at lists.llvm.org
Fri Oct 21 13:18:27 PDT 2016


Would you be opposed to me making this change in a follow-on change 
since I've already done all of my testing on this version?


On 10/21/2016 4:15 PM, Daniel Berlin wrote:
> (IE you can use getClobberingAccess always, and not worry about it)
>
> On Fri, Oct 21, 2016 at 1:14 PM, Daniel Berlin <dberlin at dberlin.org 
> <mailto:dberlin at dberlin.org>> wrote:
>
>     "Also, when using MemorySSA to check if two MemoryUses are reading
>     from
>     the same version of the heap, use the defining access instead of
>     calling
>     getClobberingAccess, since the latter can currently result in many
>     more
>     AA calls."
>
>     This should be fixed as of yesterday.
>
>
>     On Fri, Oct 21, 2016 at 1:12 PM, Geoff Berry
>     <gberry at codeaurora.org <mailto:gberry at codeaurora.org>> wrote:
>
>         gberry created this revision.
>         gberry added a reviewer: dberlin.
>         gberry added subscribers: llvm-commits, mcrosier.
>
>         When using MemorySSA, re-optimize MemoryPhis when removing a
>         store since
>         this may create MemoryPhis with all identical arguments.
>
>         Also, when using MemorySSA to check if two MemoryUses are
>         reading from
>         the same version of the heap, use the defining access instead
>         of calling
>         getClobberingAccess, since the latter can currently result in
>         many more
>         AA calls.  Once the MemorySSA use optimization tracking
>         changes are
>         done, we can remove this limitation, which should result in
>         more loads
>         being CSE'd.
>
>
>         https://reviews.llvm.org/D25881 <https://reviews.llvm.org/D25881>
>
>         Files:
>           lib/Transforms/Scalar/EarlyCSE.cpp
>           test/Transforms/EarlyCSE/memoryssa.ll
>
>
>

-- 
Geoff Berry
Employee of Qualcomm Datacenter Technologies, Inc.
  Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.  Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20161021/bf3c6e93/attachment.html>


More information about the llvm-commits mailing list