Revert r57803 "Avoid to cast the argument"

__builtin_add_overflow doesn't support double.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57805 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

include/ruby/ruby.h

@@ -360,7 +360,7 @@ rb_fix2ulong(VALUE x)
 #define RB_POSFIXABLE(f) ((f) < RUBY_FIXNUM_MAX+1)
 #define RB_NEGFIXABLE(f) ((f) >= RUBY_FIXNUM_MIN)
 #if defined HAVE_BUILTIN___BUILTIN_ADD_OVERFLOW
-# define RB_FIXABLE(f) ({SIGNED_VALUE c; !__builtin_add_overflow((f), (f), &c);})
+# define RB_FIXABLE(f) ({SIGNED_VALUE a=(f),c; !__builtin_add_overflow(a, a, &c);})
 #else
 # define RB_FIXABLE(f) (RB_POSFIXABLE(f) && RB_NEGFIXABLE(f))
 #endif