add new documentation to address pr concerns

Author: farzonl

clang/docs/LanguageExtensions.rst

@@ -1073,6 +1073,11 @@ The matrix type extension supports explicit casts. Implicit type conversion betw
     i = static_cast<matrix_5_5<int>>(d);
   }
 
+The matrix type extension will support column and row major layouts. The flag
+to change this behavior is `-fmatrix-default-layout` used like so
+`-fmatrix-default-layout=column-major` for column major and like so
+`-fmatrix-default-layout=row-major` for row major.
+
 Half-Precision Floating Point
 =============================
 

clang/docs/MatrixTypes.rst

@@ -287,6 +287,11 @@ part of the draft specification.
 The elements of a  value of a matrix type are laid out in column-major order
 without padding.
 
+To change the default order to row major use the `-fmatrix-default-layout` flag.
+This flag supports two flag argument values either `column-major` or `row-major`
+used like so `-fmatrix-default-layout=column-major`.` This flag controls the 
+memory layout of matrix types.
+
 We propose to provide a Clang option to override this behavior and allow
 contraction of those operations (e.g. *-ffp-contract=matrix*).
 

clang/docs/ReleaseNotes.rst

@@ -316,6 +316,7 @@ New Compiler Flags
 - New option ``-fsanitize-debug-trap-reasons=`` added to control emitting trap reasons into the debug info when compiling with trapping UBSan (e.g. ``-fsanitize-trap=undefined``).
 - New options for enabling allocation token instrumentation: ``-fsanitize=alloc-token``, ``-falloc-token-max=``, ``-fsanitize-alloc-token-fast-abi``, ``-fsanitize-alloc-token-extended``.
 - The ``-resource-dir`` option is now displayed in the list of options shown by ``--help``.
+- New option ``-fmatrix-default-layout`` added to control the memory layout of Clang matrix types. (e.g. ``-fmatrix-default-layout=column-major`` or ``-fmatrix-default-layout=row-major``).
 
 Lanai Support
 ^^^^^^^^^^^^^^