flang/docs/ReleaseNotes.md

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# Flang {{version}} {{in_progress}}Release Notes

::::{only} PreRelease
:::{warning}
These are in-progress notes for the upcoming LLVM {{version}} release.
Release notes for previous releases can be found on [the Download
Page](https://releases.llvm.org/download.html).
:::
::::

## Introduction

This document contains the release notes for the Flang Fortran frontend,
part of the LLVM Compiler Infrastructure, release {{version}}. Here we
describe the status of Flang in some detail, including major
improvements from the previous release and new feature work. For the
general LLVM release notes, see [the LLVM
documentation](https://llvm.org/docs/ReleaseNotes.html). All LLVM
releases may be downloaded from the [LLVM releases web
site](https://llvm.org/releases/).

Note that if you are reading this file from a Git checkout, this
document applies to the *next* release, not the current one. To see the
release notes for a specific release, please see the [releases
page](https://llvm.org/releases/).

## Major New Features

## Bug Fixes

## Non-comprehensive list of changes in this release

- Added support for the OpenMP implementation-defined extension sentinels
  (OpenMP 5.2, section 3.1): `!$omx`, `c$omx` and `*$omx` in fixed source form
  and `!$ompx` in free source form. These sentinels are recognized like their
  `omp` counterparts when OpenMP is enabled.

- The legacy array-value operations (`fir.array_load`, `fir.array_fetch`,
  `fir.array_update`, `fir.array_modify`, `fir.array_access`,
  `fir.array_amend`, `fir.array_merge_store`) have been removed from FIR,
  together with the `array-value-copy` pass that legalized them and its
  `-mmlir -disable-avc` option. Nothing in flang has produced these
  operations since the legacy (non-HLFIR) expression lowering was deleted.
  Downstream projects that still construct them must migrate to HLFIR (or
  their own legalization) before rebasing. `fir.array_coor` is unrelated
  and remains supported.

- Added support for compressed DWARF debug sections. Flang now supports
  compressing DWARF debug info in ELF object files using zlib or zstd,
  reducing debug information size in compiled binaries.

## New Compiler Flags
- Added the gfortran-compatible `-ffpe-trap=` flag, which sets the initial
  floating-point exception halting mode of the main program. It takes a
  comma-separated list of `invalid`, `zero`, `overflow`, `underflow`, `inexact`,
  and the extension `denormal`, or `none` to disable halting. See the Flang
  command line reference for the supported targets and details.

- Added `-gz` and `-gz=<format>` flags to enable compression of DWARF debug
  sections. Supported formats are `zlib`, `zstd`, and `none`.

## Windows Support

## Fortran Language Changes in Flang

## Build System Changes

## New Issues Found

## Additional Information

Flang's documentation is located in the `flang/docs/` directory in the
LLVM monorepo.

If you have any questions or comments about Flang, please feel free to
contact us on the [Discourse
forums](https://discourse.llvm.org/c/subprojects/flang/33).