| commit | 92f85fb5e86b6f3dcf95487a4c2b3c9eda680994 | [log] [tgz] |
|---|---|---|
| author | Peter Klausler <pklausler@nvidia.com> | Tue Jun 06 11:37:52 2023 -0700 |
| committer | Copybara-Service <copybara-worker@google.com> | Tue Jun 06 12:00:51 2023 -0700 |
| tree | d4394f3dadbe49c9adb549fef7a47f78387df2fc | |
| parent | 68bf3d8cca30d5c8729bf1078cfdf4f9b1b04191 [diff] |
[flang] Set "undefined" NEXTREC=n variable to 0 rather than random garbage 12.10.2.17 defines that a INQUIRE statement's NEXTREC=n output value for a unit that is not connected for direct access becomes undefined, but the current I/O runtime can fail in a confusing manner by trying to return uninitialized stack garbage. Reported on Slack by Tarun Prabhu as an intermittent failure in the gfortran regression test inquire_pre.f90. Differential Revision: https://reviews.llvm.org/D152295 GitOrigin-RevId: e468f07550c56eeb49659d02c7c5c3f79f53db6f
Flang is a ground-up implementation of a Fortran front end written in modern C++. It started off as the f18 project (https://github.com/flang-compiler/f18) with an aim to replace the previous flang project (https://github.com/flang-compiler/flang) and address its various deficiencies. F18 was subsequently accepted into the LLVM project and rechristened as Flang.
Please note that flang is not ready yet for production usage.
Read more about flang in the docs directory. Start with the compiler overview.
To better understand Fortran as a language and the specific grammar accepted by flang, read Fortran For C Programmers and flang's specifications of the Fortran grammar and the OpenMP grammar.
Treatment of language extensions is covered in this document.
To understand the compilers handling of intrinsics, see the discussion of intrinsics.
To understand how a flang program communicates with libraries at runtime, see the discussion of runtime descriptors.
If you're interested in contributing to the compiler, read the style guide and also review how flang uses modern C++ features.
If you are interested in writing new documentation, follow LLVM's Markdown style guide.
Consult the Getting Started with Flang for information on building and running flang.