Flang Biweekly Sync - Notes from the October 16th, 2019 call

Flang team,

Here are the notes from the October 16th, 2019 Flang biweekly call.

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, October 30th, 2019 at 8:30 AM Pacific Time.

The next Flang Technical Community call was Monday, October 21st, 8:30 AM Pacific Time. Craig Rasmussen discussed his early experience with the new flang compiler as the Fortran front-end for Rose.

Thank you.

Gary Klimowicz


  • Fortran Standards Committee update
  • SC 2019 – BoF for LLVM has been scheduled
  • LLVM Developer Meeting news
  • MLIR for HPC Workshop news (at LCPC 2019)
  • Flang Community Technical Call – Recap and next topic: Experience with f18 and Rose
  • F18 development update
  • Flang development update


  • Difficulties getting the call started last time

  • The new WebEx call meeting link should be https://nvmeet.webex.com/nvmeet/j.php?MTID=mb4edb8c799f69ec2dc0554acc969a162.

  • Fortran Standards Committee

  • The last meeting for 2019 is being held now in Las Vegas.

  • The goal this week is to get as close as possible to “edit” language for the feature set that was agreed to in Tokyo (REDUCE in DO CONCURRENT, enumerator types, character trimming and leading zero format controls, degree and pi trig functions, line length and statement length extensions and others: see paper 19-013 on the j3-fortran.org site)

  • The hope is that we will be able to get final proposed edits done in February for the WG5 meeting next summer.

  • Zaak Beekman asked about standardizing preprocessor behavior. Gary described the past activity in the standards committee and pointed to the documentation and tests that Peter Klausler had added to the f18 repository. Gary will continue to bring this up with J3.

  • Supercomputing 2019

  • The LLVM in HPC BoF session at SC 2019 is scheduled for Wednesday, November 20, 5:15-6:45 PM. Here’s the BoF link: https://sc19.supercomputing.org/session/?sess=sess331.

  • LLVM Developer Meeting 2019

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

  • The flang roundtable is scheduled for Tuesday, October 22, from 2 pm until 3:10 pm.

  • Eric Schweitz (NVIDIA) will present An MLIR Dialect for High-Level Optimization of Fortran.

  • 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.

  • On the October 7th call, we discussed Fortran debug metadata generation with LLVM and DWARF.

  • On the October 21st, 8:30 AM PDT, the agenda topic was experience with the new flang compiler and Rose with Craig Rasmussen.

  • We are looking for technical topics for the November 4th call.

  • 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.

  • F18 flang is still waiting to be added to the LLVM repo, but we are continuing to work with the LLVM admins; Hal is lending his support as well.

  • Johannes Doerfert recommended that the f18 team attend the biweekly OpenMP LLVM call as well. It looks like one needs to get in touch with Ravi Narayanaswamy to be invited to the call ravi.narayanaswamy@intel.com.

  • New Flang update

  • More improvements to .mod file writing.

  • Implemented resolving generic names to specific procedures.

  • Implemented more procedure call semantics checks.

  • OpenMP semantic checking continues, including contributions by David Truby.

  • Continued work on design of FIR.

  • Continued work on semantic checks for DO loops: ALLOCATE semantics.

  • 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.

  • Arm Ltd generated a pull request for Clang as a first step for the new flang driver. The pull request for adding --fortran-mode can be found here: https://reviews.llvm.org/D63607.

  • Original Flang Dev news and updates

  • More bug fixes sent to Flang.

  • Support for the Fortran 2008 BLOCK construct is on its way to Flang.

  • Arm is helping with LLVM 9 changes to Flang (differences between LLVM 8 and 9).

  • License update to Apache 2.0 with LLVM exceptions is coming very soon. This will touch nearly every file in flang.

  • We will be decoupling PGI and Flang development to shorten turnaround on pull requests, add committers.

Where we can use your help

  • Subscribe to the LLVM Flang email list: https://lists.llvm.org/cgi-bin/mailman/listinfo/flang-dev.
  • 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 these in these notes.

**Details (**Updates below are in bold)