Flang Biweekly Sync - Notes from August 21, 2019 call

Flang team,

Here are the notes from the August 21st, 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 September 4th, 2019 at 8:30 AM Pacific Time.

Thank you.

Gary Klimowicz


  • Flang Community Technical Call – Recap and next topic: Array descriptors probably
  • Fortran Standards Committee update
  • F18 development update
  • Flang development update


  • Supercomputing 2019

  • Hal submitted for an LLVM BoF session at SC 2019.

  • There won’t be an LLVM in HPC Workshop this year.

  • Fortran Standards Committee

  • WG5/PL22.3 meeting (J3 #219) held in Tokyo the week of August 5th.

  • Goal was to set the work item agenda for Fortran 202X.

  • Desire is to have a small update to the standard.

  • Items include standardizing behavior that is already implemented across most compilers; enhancing rank-agnostic programming; improvements and cleanup items for I/O; reductions in DO CONCURRENT.

  • Larger items (generic programming especially) will continue to be investigated, but were considered too large or ill-defined for inclusion in F202X. This may result in a plan for F202Y (not F203X).

  • See meeting notes and documents at https://j3-fortran.org/.

  • Flang Community Technical Biweekly Call

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

  • The August 14th call, Robyn Sampson of Intel presented on aliasing information and LLVM enhancements.

  • The next call is scheduled for August 28th, 8:30 AM PDT. The scheduled agenda topic is array descriptors.

  • Hal has a Doodle poll for potentially changing the time of this call: https://doodle.com/poll/66m8mvavg7ag2t49. The current front-runner is Tuesday, 9:00 AM Pacific time. Please make your preferences known via this link.

  • 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.

  • F18 update

  • Merged pull request for BLOCK from Arm.

  • Added more complete array spec checks.

  • Implemented a deferred analysis of pointer initializers and other constructs so that forward references can appear in more contexts.

  • Implemented folding of DIGITS and SIGN intrinsics.

  • Fixed issues with nested IMPLICIT.

  • Submitted proposal to LLVM conference for talk on Fortran and MLIR. Coordinating with Google.

  • Two pull requests to MLIR to help support Fortran Intermediate Representation have been merged.

  • More work on DO loop semantics and constraint checking, including DO CONCURRENT locality specifications. Additional tests for semantic checks added.

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

  • Flang Dev news and updates

  • More bug fixes in queue to send to Flang.

  • Improved build support for Windows and Mac coming.

  • Microsoft is investigating contributing to Flang.

  • Work continues on the BLOCK construct.

Where we can use your help

  • Respond to Hal’s Doodle poll for the meeting time for the biweekly Flang Technical Community call.
  • 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.