https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109954
--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
How about:
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -34089,7 +34089,9 @@ on x86-64 processors in 64-bit environments.
Generate code for a 16-bit, 32-bit or 64-bit environment.
The @option{-m32} option sets @code{int}, @code{long}, and pointer types
to 32 bits, and
-generates code that runs on any i386 system.
+generates code that runs in 32-bit mode. N.B., using @option{-march} might
+be required to produce code suitable for a specific CPU family, e.g.,
+@option{-march=i486}.
The @option{-m64} option sets @code{int} to 32 bits and @code{long} and
pointer
types to 64 bits, and generates code for the x86-64 architecture.
