Flang Biweekly Sync - Notes from September 4th, 2019 call

Flang team,

Here are the notes from the September 4th, 2019 Flang biweekly call. Updates are in bold.

Please be sure to let us know if you have any questions and agenda topics for the next call.

The next Flang biweekly call will be Wednesday, September 18th, 2019 at 8:30 AM Pacific Time.

The next Flang Technical Community call is scheduled for Monday, September 9th, 8:30 AM Pacific Time. The topic will be module files.

Thank you.

Gary Klimowicz


  • SC 2019 – BoF for LLVM has been accepted
  • LLVM Developer Meeting news
  • MLIR for HPC Workshop news (at LCPC 2019)
  • Flang Community Technical Call – Recap and next topic: DWARF?; moved to Mondays
  • F18 development update
  • Flang development update
  • OpenMP update form Johannes Doerfert


  • Supercomputing 2019

  • Hal’s LLVM BoF session at SC 2019 was approved. No details yet about the schedule.

  • LLVM Developer Meeting 2019

  • The LLVM Dev Meeting is October 22-23 at the San Jose Convention Center; details can be found here.

  • Eric Schweitz’s talk, An MLIR Dialect for High-Level Optimization of Fortran, was accepted.

  • MLIR for HPC Workshop 2019

  • The MLIR for HPC workshop will be held October 21st in conjunction with the 32nd Workshop on Languages and Compilers for Parallel Computing October 22-24 at Georgia tech.

  • Flang Community Technical Biweekly Call

  • Hal Finkel is hosting this call on Bluejeans, Mondays 8:30 Pacific Time, on the weeks alternating with this call. The notes for all these calls can be found in Google Docs here. Note the new day.

  • On the August 18th call, we discussed array descriptors; some people were missing on the call, so this may come up again.

  • The next call is scheduled for Monday, September 9th, 8:30 AM PDT. The scheduled agenda topic is module files.

  • Hal’s Doodle poll for changing the time of this call has concluded: https://doodle.com/poll/66m8mvavg7ag2t49. The new time is Monday, 8:30 AM Pacific time.

  • F18 as an LLVM project

  • The LLVM-hosted flang-dev mailing list has been set up. Subscribe at https://lists.llvm.org/cgi-bin/mailman/listinfo/flang-dev.

  • We will continue to support the original flang-dev@lists.flang-compiler.org and flang-sync@lists.flang-compiler.org and through August 2019. Further emails will be sent only to the LLVM lists.

  • Plan is still to upload documentation for F18 before the code, to help establish the project goals and design strategy before uploading the code. This should help establish context for the project. Steve has email to the administrators to get the initial phabricator top-level directory created.

  • NVIDIA is still blocked on adding flang to the LLVM repo, but we are continuing to work with the LLVM admins; Hal is lending his support as well.

  • F18 update

  • Fixed issues in module file generation, array references, intrinsic calls, intrinsic folding.

  • Implemented special handling for VOLATILE and ASYNCHRONOUS attributes.

  • Finished conversion of floating-point binary<->decimal templates for use at compile time and run time.

  • Worked on user procedure call protocol requirements and design.

  • More work on DO loop semantics and constraint checking, including CYCLE statements. Additional semantic checks added.

  • More work on OpenMP directive parsing and semantic checks, including Declare directives, block constructs, standalone directives, sections, atomic and critical constructs. Working through tests including SOLLVE.

  • The driver “flang” turns on semantic processing by default. This will make it easier for people to check existing codes against f18 and expanding the test suite in f18.

  • Craig Rasmussen reports that he has switch to using f18 for the Rose front-end. There’s more work to do, but he reported significant progress here.

  • Flang Dev news and updates

  • More bug fixes sent to Flang.

  • Improved build support for Windows and Mac coming.

  • Expecting CLA from Microsoft for contributing.

  • Work continues on the BLOCK construct.

  • Discussing turning more day-to-day responsibilities over to the community.

  • Arm are now committers for flang-compiler/flang-driver.

Where we can use your help

  • Subscribe to the new LLVM Flang email list: https://lists.llvm.org/cgi-bin/mailman/listinfo/flang-dev. We will be cross-posting to both flang-dev mailing lists until September.
  • Topics for the next biweekly community call and technical community call.
  • Let us know if you have presentations or meetings relevant to the Flang community. We will publicize them in these notes.