[llvm-branch-commits] [clang] [llvm] Add PowerPC/AIX related release notes to LLVM 21.1.0 (PR #154465)

[Amy Kwan via llvm-branch-commits]

https://github.com/amy-kwan created https://github.com/llvm/llvm-project/pull/154465

This PR aims to add release notes to LLVM 21.1.0 for PPC/AIX, and other related release notes.

>From 81a4f1f94f35055b9389b1d8c3b810aa7e07a41f Mon Sep 17 00:00:00 2001
From: Amy Kwan <amy.kwan1 at ibm.com>
Date: Wed, 20 Aug 2025 04:04:40 +0000
Subject: [PATCH] Add PowerPC/AIX related release notes to LLVM 21.1.0

---
 clang/docs/ReleaseNotes.rst | 10 ++++++++++
 llvm/docs/ReleaseNotes.md   | 18 ++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index f4f7dd8342d92..e60fc22464ccd 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -1125,9 +1125,19 @@ CUDA/HIP Language Changes
 CUDA Support
 ^^^^^^^^^^^^
 
+PowerPC Support
+^^^^^^^^^^^^^^^
+
+* Add `__dmr1024` type for Dense Math Facility.
+* Add prototype for Dense Math Facility integer calculation builtins.
+
 AIX Support
 ^^^^^^^^^^^
 
+* Fixed `-print-runtime-dir` to fallback to the target subdirectory (rather than OS subdirectory) if the runtime path is not found.
+* Fixed `-print-runtime-dir` to find the correct runtime path if the triple has "unknown" as the environment component.
+* Changed AIX targets to use the per-target runtime directories for compiler runtimes (i.e. `lib/clang/20/lib/aix` became `lib/clang/21/lib/powerpc-ibm-aix` and `clang/21/lib/powerpc64-ibm-aix`).
+
 NetBSD Support
 ^^^^^^^^^^^^^^
 
diff --git a/llvm/docs/ReleaseNotes.md b/llvm/docs/ReleaseNotes.md
index a126d7ae1ab4a..8e97f25ba5e40 100644
--- a/llvm/docs/ReleaseNotes.md
+++ b/llvm/docs/ReleaseNotes.md
@@ -159,6 +159,18 @@ Changes to the MIPS Backend
 Changes to the PowerPC Backend
 ------------------------------
 
+* Add spill and restore for DMR and DMRp registers.
+* Prototype various Dense Math Facility instructions, and intrinsics for basic enablement, insert/extract, integer and FP calculations.
+* Add prototype for Dense Math Facility cryptography instructions.
+* Implement load/stores prototype for v1024i1, v2048i1.
+* Support conversion between f16 and f128.
+* Change default for auto gen stxvp for cpu=future.
+* Setup initial JITLink build support for XCOFF.
+* Add an API to derive the default feature set from a CPU name within the TargetParser
+  (e.g. `pwr10` -> `+vsx`,`+isa3_1`,`+mma`). Clang now uses this to populate the `target-feature`
+  list when `-mcpu` is provided for PowerPC.
+* Various bug fixes and codegen improvements.
+
 Changes to the RISC-V Backend
 -----------------------------
 
@@ -220,6 +232,7 @@ Changes to the RISC-V Backend
 * Removed -mattr=+no-rvc-hints that could be used to disable parsing and generation of RVC hints.
 * Adds assembler support for the Andes `XAndesvsintload` (Andes Vector INT4 Load extension).
 * Adds assembler support for the Andes `XAndesbfhcvt` (Andes Scalar BFLOAT16 Conversion extension).
+* Add combine for shadd family of instructions.
 
 Changes to the WebAssembly Backend
 ----------------------------------
@@ -352,6 +365,11 @@ Other Changes
   communication with the distributor.
   ([#47468](https://github.com/llvm/llvm-project/issues/47468)).
 
+Changes to the Profile Runtime
+---------------------
+
+* On AIX, avoid using mmap when reading profile files from a non-local filesystem.
+
 External Open Source Projects Using LLVM {{env.config.release}}
 ===============================================================