[gcc r16-8109] RISC-V: Document big-endian support as experimental

[Kito Cheng]

https://gcc.gnu.org/g:4565290a96136837a48cb1ead202b19b1c6118fb

commit r16-8109-g4565290a96136837a48cb1ead202b19b1c6118fb
Author: Kito Cheng <kito.cheng@sifive.com>
Date:   Mon Mar 16 17:00:43 2026 +0800

    RISC-V: Document big-endian support as experimental
    
    The RISC-V big-endian ABI is not yet stable, add a note to the
    -mbig-endian option documentation to warn users that support is
    experimental and could change in incompatible ways.
    
    gcc/ChangeLog:
    
            * doc/invoke.texi: Add experimental warning for RISC-V
            big-endian support.

Diff:
---
 gcc/doc/invoke.texi | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 4b8200152157..a93aa2145655 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -31304,6 +31304,8 @@ width as the alignment value, and @samp{natural} which uses natural alignment.
 @item -mbig-endian
 Generate big-endian code.  This is the default when GCC is configured for a
 @samp{riscv64be-*-*} or @samp{riscv32be-*-*} target.
+Support for RISC-V big-endian is experimental.  The ABI is not yet stable
+and could change in incompatible ways in future releases.
 
 @opindex mlittle-endian
 @item -mlittle-endian