Re: Bug? flow_find_cross_jump deletes USE insns ...

[Jan Hubicka <jh at suse dot cz>]

> On Mon, Jan 14, 2002 at 04:56:53PM +0100, Ulrich Weigand wrote:
> > The prolog on S/390 generates a USE insn for the GOT register,
> > because the GOT pointer must be loaded even if it isn't used
> > in the routine (because the PLT stubs rely on the register).
> 
> This isn't going to work.  Bare USE insns aren't meaningful
> after reload.  You need to add the USE to the call insn.  You
> can do this either inside the call pattern itself, or by adding
> it to the CALL_INSN_FUNCTION_USAGE expr_list.

As I tried previously, CALL_INSN_FUCNTION_USGE way is tricky.
At least on i386, you don't need GOT when function is called indirectly,
so I don't add it to the FUSAGE, but when the indirect call is changed
to direct, I get wrong insn, as I can't check validity of FUSAGE in
the pattern.
It is better to use separate USE IMO.

Honza
> 
> 
> r~