------- Additional Comments From dave at hiauly1 dot hia dot nrc dot ca
2005-08-13 21:46 -------
Subject: Re: [4.0.x regression] Generates wrong code for funcptr comparison
> Bah, while this is probably going to happen for hppa-linux, it'snever going
> to happen for hppa-hpux. GCC's treatment of functionpointers here is just
> WRONG.There are a couple of issues. The most serious is the following:We
> have the following code from __pthread_sigaction in the .i file: if (old ==
> ((__sighandler_t) 1) || old == ((__sighandler_t) 0) || old ==
> ((__sighandler_t) -1)) __sighandler[sig].old = (arch_sighandler_t)
> act->__sigaction_handler.sa_handler;This is what the above turns into in the
> tree dump filebug321785.c.t02.original: if ((void (*<T2bd>) (int))
> old - 2B > -4B) { __sighandler[sig].old = (void
> (*<T431>) (int, struct sigcontext *)) act->__sigaction_handler.sa_handler;
> }I don't believe that the transformation is valid. Also, it not
> validC to do relational comparisons where one of the operands is a
> functionpointer. See 6.5.8 (2).do_compare_and_jump doesn't check code before
> canonicalizing functionpointer!
s.!
> I think we need an assert in do_compare_and_jump to catchinvalid function
> pointer comparisons.
Yuck. I used Konqueror to add this comment and it totally botched up
the white space ;(
Dave
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23369
