[docs] Add clang/llvm release notes for mipsel-windows-* targets

[hpoussin]

While very experimental support was already present in LLVM 20, this is now usable.

[llvmbot]

@llvm/pr-subscribers-clang

Author: Hervé Poussineau (hpoussin)

Changes

While very experimental support was already present in LLVM 20, this is now usable.

This is still related to the following PRs:

• [libc++] Define __libcpp_recursive_mutex_t on MIPS architecture #144272
• [compiler-rt][sanitizer] Add Windows MIPS32 support #145110
• [Mips] Correctly define IntPtrType #145158

---

Full diff: https://github.com/llvm/llvm-project/pull/147133.diff

2 Files Affected:

• (modified) clang/docs/ReleaseNotes.rst (+2)
• (modified) llvm/docs/ReleaseNotes.md (+2)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 9a94c4bcd9980..d963286531db8 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -991,6 +991,8 @@ Windows Support
   extensions are enabled. This allows for properly processing ``intsafe.h`` in
   the Windows SDK.
 
+- Clang now supports `mipsel-windows-gnu` and `mipsel-windows-msvc` targets
+
 LoongArch Support
 ^^^^^^^^^^^^^^^^^
 
diff --git a/llvm/docs/ReleaseNotes.md b/llvm/docs/ReleaseNotes.md
index 26384d94d04fc..b3b77ede16098 100644
--- a/llvm/docs/ReleaseNotes.md
+++ b/llvm/docs/ReleaseNotes.md
@@ -150,6 +150,7 @@ Changes to the MIPS Backend
 ---------------------------
 
 * `-mcpu=i6400` and `-mcpu=i6500` were added.
+* Added support for `mipsel-windows-gnu` and `mipsel-windows-msvc` targets
 
 Changes to the PowerPC Backend
 ------------------------------
@@ -222,6 +223,7 @@ Changes to the Windows Target
 
 * `fp128` is now passed indirectly, meaning it uses the same calling convention
   as `i128`.
+* Added support for `mipsel-windows-gnu` and `mipsel-windows-msvc` targets
 
 Changes to the X86 Backend
 --------------------------

[brad0]

Missing a period at the end of each entry.

[hpoussin]

Missing a period at the end of each entry.

Entries updated.

[hpoussin]

Any possibility to have it merged before branching?

[hpoussin]

@brad0, ping

[brad0]

This should be taken and created as a MR against the 21 release.

[hpoussin]

Rebased on branch origin/release/21.x, and updated target branch of this PR, but I'm not sure it is enough.

[hpoussin]

@brad0, it is what you expected?

[github-actions]

@hpoussin (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR.