[clang] 0b903ef - Re-add release notes for GCC ABI compatibility for non-POD in packed structs

[David Blaikie via cfe-commits]

Author: David Blaikie
Date: 2022-05-22T01:15:34Z
New Revision: 0b903ef6aa0976a60d3f448837f3c43adaf09cc1

URL: https://github.com/llvm/llvm-project/commit/0b903ef6aa0976a60d3f448837f3c43adaf09cc1
DIFF: https://github.com/llvm/llvm-project/commit/0b903ef6aa0976a60d3f448837f3c43adaf09cc1.diff

LOG: Re-add release notes for GCC ABI compatibility for non-POD in packed structs

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.rst

Removed: 
    


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diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 5d1b12504f787..a889c74a55239 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -424,6 +424,12 @@ OpenCL C Language Changes in Clang
 ABI Changes in Clang
 --------------------
 
+- GCC doesn't pack non-POD members in packed structs unless the packed
+  attribute is also specified on the member. Clang historically did perform
+  such packing. Clang now matches the gcc behavior (except on Darwin and PS4).
+  You can switch back to the old ABI behavior with the flag:
+  ``-fclang-abi-compat=13.0``.
+
 OpenMP Support in Clang
 -----------------------