[flang-dev] Flang Biweekly Sync - Notes from the September 30, 2020 call

Gary Klimowicz via flang-dev flang-dev at lists.llvm.org
Thu Oct 1 09:45:52 PDT 2020


________________________________
Flang team,

Here are the notes from the September 30, 2020 Flang Community biweekly call.

“LLVM Flang” is the Fortran 2018 compiler being developed as part of the LLVM project, and located in the LLVM monorepo (github.com/llvm/llvm-project).

“Classic Flang” is the original Flang Fortran 2003/2008 compiler located at github.com/flang-compiler/flang.

Let me know if you have any topics you would like covered in the next call.

Upcoming calls (all times Pacific time):
Call
When
LLVM Flang Technical Community call
Monday, October 5, 8:30 AM
LLVM Alias Analysis call
Tuesday, October 6, 2020 at 10:00 AM
(to be replaced by an 2020 Virtual LLVM Dev Meeting Roundtable)
Classic Flang biweekly call
Wednesday, October 7, 2020 at 8:30 AM
OpenMP developer call
Thursday, October 8, 2020 at 8:00 AM
Flang biweekly call (this call)
Wednesday, October 14, 2020 at 8:30 AM

Information for joining these calls and the Flang Slack workspace is at the end of this email.

Thank you.

Gary


Agenda

  *   LLVM Virtual Developers’ Meeting
  *   LLVM Flang Technical Call agenda
  *   LLVM Flang development update
  *   Classic Flang update

Highlights


  *   LLVM Virtual Developers’ Meeting October 6-8
     *   http://llvm.org/devmtg/2020-09/
     *   Flang Roundtable: Pat McCormick, Alexis Perry-Holby, Hal Finkel, Johannes Doerfert, Steve Scalpone, Eric Schweitz, Kelvin Li, Tarique Islam (Tue Oct 6, 10:35 PT)
     *   Lightning talk: Valentin Clement: OpenACC support in Flang with a MLIR dialect (Wed October 7, 10:40 AM PT)
     *   Lightning talk: Steve Scalpone: Flang Update (Wed October 7, 12:00 PM PT)
     *   Technical talk: Johannes Doerfert, Stefan Stipanovic: (OpenMP) Parallelism-Aware Optimizations (Thu October 8, 12:55 PM PT)
     *   Technical Talk: Kelvin Li, Tarique Islam: Towards a representation of arbitrary alias graph in LLVM IR for Fortran code (Thu October 8, 12:55 PM PT)


  *   Flang Community Technical Biweekly Call
     *   Next call: October 5: Overview of reviews; Valentin Clement, OpenACC 3.0 in Flang
     *   Please add both small and large technical topics to the Google Doc for the technical call. The link to the Google Doc can be found in the notes below.
     *   A new invitation will be sent.


  *   LLVM Flang updates

     *   More improvements for supporting Fortran 77 programs
     *   OpenACC loop construct lowering
     *   Many updates for Windows and MSVC
     *   Additional updates to flang driver (dependency updates, option handling)
     *   Lit tests for OpenMP 5.0 constructs (Sections 2.5, 2.7.1-2.7.4, etc.)
     *   Hal Finkel requested an updated plan on upstreaming fir-dev to the LLVM monorepo, now that we have Fortran 77 functionality in place


  *   Classic Flang Dev news and updates
The following pull requests have been merged into Classic Flang:
     *   #1<https://github.com/flang-compiler/classic-flang-llvm-project/pull/1>: classic-flang-llvm-project: Port release_90 patches to LLVM 10 monorepo
     *   #658<https://github.com/flang-compiler/flang/pull/658>: Fix in preprocessing for Flexi app
     *   #756<https://github.com/flang-compiler/flang/pull/756>: Fix ICE interf:new_symbol_and_link symbol not found
     *   #888<https://github.com/flang-compiler/flang/pull/888>: flang gen-exec does not show routine variables with parameter attribute; there are multiple pull requests that this includes (details below)
     *   #921<https://github.com/flang-compiler/flang/pull/921>: Correction of representation of string (character type) constants
The following pull requests are being reviewed:

     *   #919<https://github.com/flang-compiler/flang/pull/919>: Fix issue #670: Internal compiler error (from NVIDIA Fortran)
     *   #902<https://github.com/flang-compiler/flang/pull/902>: flang gen-exec doesnt print allocatable array in debugger
     *   #913<https://github.com/flang-compiler/flang/pull/913>: flang gen-exec does not generate DW_AT_associated or DW_AT_allocated
     *   #925<https://github.com/flang-compiler/flang/pull/925>: [DebugInfo] Flang should generate correct IR for assumed size array
     *   #926<https://github.com/flang-compiler/flang/pull/926>: [DebugInfo] Support for non-contiguous assumed shape array



Details (Updates below are in bold)


  1.  Flang on GitHub
·         LLVM Flang is in https://github.com/llvm/llvm-project/tree/master/flang.
·         There have been 2,680 commits for LLVM Flang encompassing over 164,000 lines of code, documentation, CMakefiles and tests.
·         There have been 1,698 total commits to Classic Flang in github.com/flang-compiler/flang.
·         There are 541 people who have “starred” the Classic Flang repo and 82 forks.



  1.  Flang Community Technical Call (Hosted by Hal Finkel)

  *   The last technical call topic was “Using MLIR’s affine dialect with FIR” (Rajan Walia, NVIDIA).


  *   The next technical community call will be Monday, October 5, 8:30 AM PT.

     *   Valentin Clement: OpenACC 3.0
     *   Outstanding reviews


  *   Future Topics and tentative dates:

     *   Build times for the compiler.
     *   Please feel free to add agenda topics to the Google Doc: https://docs.google.com/document/d/1Z2U5UAtJ-Dag5wlMaLaW1KRmNgENNAYynJqLW2j2AZQ/.


  1.  The LLVM alias analysis call was held Tuesday, September 8.

  *   The agenda document is at https://docs.google.com/document/d/1ybwEKDVtIbhIhK50qYtwKsL50K-NvB6LfuBsfepBZ9Y.

     *   Status of the Full Restrict Patches (Joeren Dobbelaere has posted patches ready for review).
     *   Michael Kruse asked about a relationship between this provenance tracking and pointer comparison folding; there are notes from the discussion in the document.


  *   The next alias analysis call is scheduled for Tuesday, October 6. This is to be replaced by a 2020 Virtual LLVM Dev Mtg Round Table.



  1.  OpenMP Technical Call

  *   The call is held every Thursday at 8 am PDT/4 pm BST/8.30 pm IST to coordinate OpenMP work. The primary agenda item of the call is a development update from the engineers involved.
  *   Participants include AMD, Arm, the US National Labs and BSC.
  *   Kiran Kumar (email in CC) from AMD hosts the call. Please let him know if you plan to join and need an invite.


  1.  Flang community

  *   Website: www.flang-compiler.org<http://www.flang-compiler.org> redirects to http://github.com/flang-compiler/flang.
  *   Wiki: https://github.com/flang-compiler/flang/wiki is the Flang wiki page where the most up-to-date build instructions and news can be found.


  *   Issues:

     *   Issues for LLVM flang should be reported in Bugzilla: https://bugs.llvm.org/. Use the “flang” tag for flang-related issues, please.
     *   Issues for Classic Flang can be reported to https://github.com/flang-compiler/flang/issues.


  *   LLVM mailing lists: There are now two mailing lists hosted by llvm.org:

     *   The flang-dev mailing list: subscribe at https://lists.llvm.org/cgi-bin/mailman/listinfo/flang-dev. These biweekly notes are sent to this email list.
     *   The flang-commits mailing list: subscribe at https://lists.llvm.org/cgi-bin/mailman/listinfo/flang-commits.


  *   Slack: The flang-compiler.slack.com workspace is used for informal real-time communication in the Flang community. The invitation link can be found at the end of this email.



  1.  What we’re up to with the llvm-project/flang Fortran 2018 compiler

  *   On GitHub: The source code LLVM Flang is available on https://github.com/llvm/llvm-project/tree/master/flang. It’s recommended to start in the “docs” directory.


  *   Public plan: The team maintains a plan for upcoming Flang work at https://github.com/orgs/flang-compiler/projects/. This reflects current LLVM Flang priorities and context for the project and its long-term goals. (OpenMP work for flang, clang ad OpenMPIR is tracked separately.)


  *   Status: We continue development. Recent work includes:

     *   More improvements for supporting Fortran 77 programs
     *   OpenACC loop construct lowering
     *   Many updates for Windows and MSVC
     *   Installed ‘flang’ permissions update (from 0700)
     *   Additional updates to flang driver (CMake updates, option handling)
     *   Lit tests for OpenMP 5.0 constructs (Sections 2.5, 2.7.1-2.7.4, etc.)
     *   Continued work on lowering FORALL construct
     *   Completed semantic analysis for FINAL procedures
     *   Hal Finkel requested an updated plan on upstreaming fir-dev to the LLVM monorepo, now that we have Fortran 77 functionality in place; NVIDIA will provide an update




  1.  What we’re up to with Classic Flang

     *   We use the flang-compiler.slack.com channel #classic-flang-pull-requests to coordinate what pull requests we are working on.

     *   Recent fixes pushed to Classic Flang master
        *   #1<https://github.com/flang-compiler/classic-flang-llvm-project/pull/1>: classic-flang-llvm-project: Port release_90 patches to LLVM 10 monorepo
        *   #658<https://github.com/flang-compiler/flang/pull/658>: Fix in preprocessing for Flexi app
        *   #756<https://github.com/flang-compiler/flang/pull/756>: Fix ICE interf:new_symbol_and_link symbol not found
        *   #888<https://github.com/flang-compiler/flang/pull/888>: flang gen-exec does not show routine variables with parameter attribute. There are multiple pull requests that this should be bundled with:
           *   #863<https://github.com/flang-compiler/flang/pull/863>: Support for -gdwarf-5 in flang2
           *   #921<https://github.com/flang-compiler/flang/pull/921>: Correction of representation of string (character type) constants
           *   Flang-driver #94<https://github.com/flang-compiler/flang-driver/pull/94>: Support for DWARF 4/5 and fix of issues related to -gdwarf-X options
        *   #921<https://github.com/flang-compiler/flang/pull/921>: Correction of representation of string (character type) constants
     *   Pull requests in review:
        *   #919<https://github.com/flang-compiler/flang/pull/919>: Fix issue #670: Internal compiler error (from NVIDIA Fortran)
        *   #902<https://github.com/flang-compiler/flang/pull/902>: flang gen-exec doesnt print allocatable array in debugger
        *   #913<https://github.com/flang-compiler/flang/pull/913>: flang gen-exec does not generate DW_AT_associated or DW_AT_allocated
        *   #925<https://github.com/flang-compiler/flang/pull/925>: [DebugInfo] Flang should generate correct IR for assumed size array
        *   #926<https://github.com/flang-compiler/flang/pull/926>: [DebugInfo] Support for non-contiguous assumed shape array
     *   Outstanding pull requests: https://github.com/flang-compiler/flang/pulls for the current list of pull requests.
     *   Outstanding issues: Please refer to the Issues section on GitHub for flang-compiler/flang<https://github.com/flang-compiler/flang/issues> and flang-compiler/flang-driver<https://github.com/flang-compiler/clang/issues>.
     *   Arm is planning to set up buildbots for Classic Flang. We should also set up OpenPOWER and x86 buildbots.


  *   Packaging and Binary Releases:

  *   Spack: Spack packages for Flang have been updated. There is also a spack package for f18, based on the flang-compiler/f18 repository. From Nick Romero: “`spack install flang%gcc` and `spack install flang+cuda%gcc` build." Due to the number of questions he receives about building Classic Flang, he will investigate using “master” as the default branch for Spack installs (and not the older labeled tags).


  *   Classic Flang Fortran 2008 features
Current status of Fortran 2008 features can be found at https://github.com/flang-compiler/flang/wiki/Fortran-2008.



  1.  Logistics
Flang Community Biweekly Call (this call)

     *   General updates on the Flang project, both LLVM Flang and Classic Flang.
     *   Biweekly WebEx hosted by NVIDIA (which these notes cover).
     *   The meeting link for this biweekly call is https://nvmeet.webex.com/nvmeet/j.php?MTID=mb4edb8c799f69ec2dc0554acc969a162.

Flang Community Technical Biweekly Call

     *   Technical topics call.
     *   Hal Finkel hosts this call on Bluejeans<https://bluejeans.com/625064848>, Mondays 8:30 Pacific Time, on the weeks alternating with regular Flang biweekly call. The notes for all these calls can be found in Google Docs here<https://docs.google.com/document/d/1Z2U5UAtJ-Dag5wlMaLaW1KRmNgENNAYynJqLW2j2AZQ/>.
Meeting URL: https://bluejeans.com/625064848?src=join_info
Meeting ID: 625 064 848
Want to dial in from a phone? Dial one of the following numbers:
+1.408.317.9254 (US (San Jose))
+1.866.226.4650 (US Toll Free)
(see all numbers - https://www.bluejeans.com/premium-numbers)
Enter the meeting ID and passcode followed by #
Connecting from a room system?
Dial: bjn.vc or 199.48.152.152 and enter your meeting ID & passcode

Classic Flang Biweekly Technical Call

     *   For people working on Classic Flang, the original Flang Fortran 2003/2008 compiler.
     *   The call is held every other Wednesday in the same week as the LLVM Flang Technical call (alternate week with the Flang Community Biweekly call).

The agenda is available here: https://docs.google.com/document/d/1-OuiKx4d7O6eLEJDBDKSRnSiUO2rgRR-c2Ga4AkrzOI.

Join the Microsoft Teams Meeting at https://teams.microsoft.com/l/meetup-join/19%3ameeting_YjM5YjlmNGEtMjA0MS00MTRlLTg5ZjUtOTM1ZGIxOTU2NWQy%40thread.v2<https://teams.microsoft.com/l/meetup-join/19%3ameeting_YjM5YjlmNGEtMjA0MS00MTRlLTg5ZjUtOTM1ZGIxOTU2NWQy%40thread.v2/0?context=%7b%22Tid%22%3a%22f34e5979-57d9-4aaa-ad4d-b122a662184d%22%2c%22Oid%22%3a%223641875c-ef5b-4767-8105-0787a195852f%22%7d>

+442033215213 (Toll)
Conference ID: 349 328 047#
Local numbers<https://dialin.teams.microsoft.com/7bdb65cd-97d0-44fe-bc03-bf8072eadc33?id=349328047>
Join with a video conferencing device
784150312 at t.plcm.vc<mailto:784150312 at t.plcm.vc> VTC Conference ID: 1220440737

LLVM Alias Analysis Technical Call

     *   For people working on improvements to LLVM alias analysis.
     *   Hal Finkel hosts this call on Bluejeans<https://bluejeans.com/101176001>, Tuesdays 10:00 AM Pacific Time, every 4 weeks. The notes for all these calls can be found in Google Docs here<https://docs.google.com/document/d/1ybwEKDVtIbhIhK50qYtwKsL50K-NvB6LfuBsfepBZ9Y/>.
Meeting URL: https://bluejeans.com/101176001?src=join_info
Meeting ID: 101 176 001
Want to dial in from a phone? Dial one of the following numbers:
+1.312.216.0325 (US (Chicago))
+1.408.740.7256 (US (San Jose))
+1.866.226.4650 (US Toll Free)
(see all numbers - https://www.bluejeans.com/premium-numbers)
Enter the meeting ID and passcode followed by #
Connecting from a room system?
Dial: bjn.vc or 199.48.152.152 and enter your meeting ID & passcode

OpenMP Technical Call

·         Kiran Kumar T P (KiranKumar.TP at amd.com<mailto:KiranKumar.TP at amd.com>) from AMD hosts this weekly call on Microsoft Teams, Thursdays 8:00 AM Pacific time.

·         Please let Kiran know if you plan to join and need an invite.

o    Teams Call Link: https://bit.ly/39eQW3o

o    Minutes: https://docs.google.com/document/d/1yA-MeJf6RYY-ZXpdol0t7YoDoqtwAyBhFLr5thu5pFI

o    Project Management: https://docs.google.com/spreadsheets/d/1FvHPuSkGbl4mQZRAwCIndvQx9dQboffiD-xD0oqxgU0/<https://docs.google.com/spreadsheets/d/1FvHPuSkGbl4mQZRAwCIndvQx9dQboffiD-xD0oqxgU0/edit#gid=0>

Flang Slack Workspace

     *   There is a Slack workspace dedicated to Flang, flang-compiler.slack.com.
     *   There are a number of topic-oriented channels available (e.g., #driver, #f18-semantics, #f18-tooling, #fir).
     *   Add yourself via the invitation link https://join.slack.com/t/flang-compiler/shared_invite/zt-2pcn51lh-VrRQL_YUOkxA_1CEfMGQhw

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