* doc/install.texi (Specific, sparc-sun-solaris2*) Copy documentation

        about 64-bit support from the 3.0_branch version.

From-SVN: r46350

gcc/doc/install.texi

@@ -3251,6 +3251,18 @@ This is Sun bug 4237974.  This is fixed with patch 108908-02 for Solaris
 2.6 and has been fixed in later (5.x) versions of the assembler,
 starting with Solaris 7.
 
+Starting with Solaris 7, the operating system is capable of executing
+64-bit SPARC V9 binaries.  GCC 3.0 doesn't properly support this yet.
+Although some patches or recipes to enable this support have been posted
+to various newsgroups and mailing lists, we recommend against using
+them, since the compiler may either crash or, worse, silently generate
+bad code.  If you really need this capability now, you might try a CVS
+version of GCC 3.1, which will fully support this.  If all you want is
+code tuned for the UltraSPARC CPU, you should try the
+@option{-mtune=ultrasparc} option instead, which should be safe from
+those bugs and produce code that, unlike full 64-bit code, can still run
+on non-UltraSPARC machines.
+
 @html
 </p>
 <hr>