[flang-commits] [flang] [flang] Document experimental support for multi-image features (PR #178011)

[Dan Bonachea via flang-commits]

https://github.com/bonachea created https://github.com/llvm/llvm-project/pull/178011

This PR updates flang's Fortran standard conformance documentation to reflect the recent addition of experimental support for multi-image features.

PRs implementing that support include:
* #151675
* #154081
* #154770
* #154166
* #165573


>From 510e25df1d523a093ff64b56e431ffc0ca4adb79 Mon Sep 17 00:00:00 2001
From: Dan Bonachea <dobonachea at lbl.gov>
Date: Fri, 23 Jan 2026 20:23:01 -0800
Subject: [PATCH 1/2] flang/docs/FortranStandardsSupport: Document experimental
 support for multi-image features

Annotate the F2018 multi-image features that now have experimental support.

Sort the list to group related features with experiemental support.
---
 flang/docs/FortranStandardsSupport.md | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/flang/docs/FortranStandardsSupport.md b/flang/docs/FortranStandardsSupport.md
index 97363dbd048a3..2d531e886f0eb 100644
--- a/flang/docs/FortranStandardsSupport.md
+++ b/flang/docs/FortranStandardsSupport.md
@@ -67,25 +67,24 @@ the multi-image execution. The table entries are based on the document [The new
 | Feature                                                    | Status | Comments                                                |
 |------------------------------------------------------------|--------|---------------------------------------------------------|
 | Asynchronous communication                                 | P      | Syntax is accepted |
-| Teams                                                      | N      | Multi-image/Coarray feature |
-| Image failure                                              | P      | Multi-image/Coarray feature. stat_failed_image is added |
-| Form team statement                                        | N      | Multi-image/Coarray feature |
-| Change team construct                                      | N      | Multi-image/Coarray feature |
+| Collective subroutines                                     | P      | Experimental support via [PRIF](ParallelMultiImageFortranRuntime.md), missing co_reduce |
+| Teams                                                      | P      | Experimental support via [PRIF](ParallelMultiImageFortranRuntime.md) |
+| Form team statement                                        | P      | Experimental support via [PRIF](ParallelMultiImageFortranRuntime.md) |
+| Change team construct                                      | P      | Experimental support via [PRIF](ParallelMultiImageFortranRuntime.md) |
+| Sync team construct                                        | P      | Experimental support via [PRIF](ParallelMultiImageFortranRuntime.md) |
+| Intrinsic functions get_team and team_number               | P      | Experimental support via [PRIF](ParallelMultiImageFortranRuntime.md) |
+| Intrinsic function image_index                             | P      | Experimental support via [PRIF](ParallelMultiImageFortranRuntime.md) |
+| Intrinsic function num_images                              | P      | Experimental support via [PRIF](ParallelMultiImageFortranRuntime.md) |
+| Intrinsic function this_image                              | P      | Experimental support via [PRIF](ParallelMultiImageFortranRuntime.md) |
+| Image failure and stat= specifiers                         | P      | Multi-image/Coarray feature. stat_failed_image is added |
 | Coarrays allocated in teams                                | N      | Multi-image/Coarray feature |
 | Critical construct                                         | N      | Multi-image/Coarray feature |
 | Lock and unlock statements                                 | N      | Multi-image/Coarray feature |
 | Events                                                     | N      | Multi-image/Coarray feature |
-| Sync team construct                                        | N      | Multi-image/Coarray feature |
 | Image selectors                                            | N      | Multi-image/Coarray feature |
-| Intrinsic functions get_team 	and team_number              | N      | Multi-image/Coarray feature |
-| Intrinsic function image_index                             | N      | Multi-image/Coarray feature |
-| Intrinsic function num_images                              | N      | Multi-image/Coarray feature |
-| Intrinsic function this_image                              | N      | Multi-image/Coarray feature |
 | Intrinsic move_alloc extensions                            | P      | Multi-image/Coarray feature |
 | Detecting failed and stopped images                        | N      | Multi-image/Coarray feature |
-| Collective subroutines                                     | N      | Multi-image/Coarray feature |
 | New and enhanced atomic subroutines                        | N      | Multi-image/Coarray feature |
-| Failed images and stat= specifiers                         | N      | Multi-image/Coarray feature |
 | Intrinsic function coshape                                 | N      | Multi-image/Coarray feature |
 
 ## Fortran 2008

>From 40cb75fbac5912c78667e1dfb5774f7618de9eac Mon Sep 17 00:00:00 2001
From: Dan Bonachea <dobonachea at lbl.gov>
Date: Fri, 23 Jan 2026 20:36:09 -0800
Subject: [PATCH 2/2] flang/docs/ParallelMultiImageFortranRuntime: Document
 known implementation of PRIF

---
 flang/docs/ParallelMultiImageFortranRuntime.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/flang/docs/ParallelMultiImageFortranRuntime.md b/flang/docs/ParallelMultiImageFortranRuntime.md
index 6dd21a420d787..f40a4274d7dee 100644
--- a/flang/docs/ParallelMultiImageFortranRuntime.md
+++ b/flang/docs/ParallelMultiImageFortranRuntime.md
@@ -15,3 +15,8 @@ Fortran's multi-image parallel features.
 
 The current revision of the PRIF specification is here:
 <https://doi.org/10.25344/S46S3W>
+
+Library implementations of PRIF include:
+
+* [Caffeine](https://go.lbl.gov/caffeine) - portable open-source implementation targeting shared- and distributed-memory systems running Linux or macOS
+