This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: Non-call exceptions versus cse
- From: Andrew Haley <aph at redhat dot com>
- To: kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)
- Cc: rth at redhat dot com, gcc-patches at gcc dot gnu dot org
- Date: Mon, 25 Nov 2002 19:27:58 +0000 (GMT)
- Subject: Re: Non-call exceptions versus cse
- References: <10211251841.AA28977@vlsi1.ultra.nyu.edu>
Richard Kenner writes:
> > I think both are needed: you set a flag if you cross an EH (but not just
> > a block) boundary and you test that flag if the insn may trap.
>
> Why do you think you need to distinguish? This is no
> different from a branch -- it's a control-flow transfer.
>
> I'm sorry, you lost me. Distinguish between what and what?
>
> Why does it make a difference if we move a trapping insn into another
> basic block if both are in the same EH region?
The idea is that
{
int tmp = <may trap operation>;
var = tmp;
}
should not update var if the operation traps.
Andrew.