infinite loop in find_avail_set

[Richard Henderson]

Contrary to Jeff's analysis, I'd like to present a test case that does
in fact result in a loop.  I returned to my computer this morning to
find that compiling yyparse in cexp.c for stage1 of new_ia32_branch does
not complete. 

There's a built tree at /bcpl/int/rth/egcs/build/new/gcc with z.i being
the preprocessed test case, if you have time to look at it quickly.
Otherwise I'll look at it further when I get to the office.


r~