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Re: PR19578: noreturn vs. function pointer propagation part 2
- From: Jeffrey A Law <law at redhat dot com>
- To: Richard Sandiford <rsandifo at redhat dot com>
- Cc: Diego Novillo <dnovillo at redhat dot com>, gcc-patches at gcc dot gnu dot org
- Date: Fri, 28 Jan 2005 10:20:54 -0700
- Subject: Re: PR19578: noreturn vs. function pointer propagation part 2
- Organization: Red Hat, Inc
- References: <email@example.com> <41F27889.firstname.lastname@example.org> <email@example.com>
- Reply-to: law at redhat dot com
On Wed, 2005-01-26 at 22:28 +0000, Richard Sandiford wrote:
> Diego Novillo <firstname.lastname@example.org> writes:
> > When building the flowgraph, consider indirect calls block
> > terminators. It's probably the easiest approach, but it may have a
> > negative impact on some codes with many indirect calls (see
> > stmt_ends_bb_p).
> OK, the patch below does that... kind of. It actually changes
> is_ctrl_altering_stmt (the predicate used by stmt_ends_bb_p)
> so that indirect calls are conservatively treated as being
> Bootstrapped & regression tested on i686-pc-linux-gnu. OK to install?
> PR tree-optimization/19578
> * tree-cfg.c (is_ctrl_altering_stmt): Return true for indirect calls.
I had to sit down and think about this for a while -- I was somewhat
worried that it might pessimize code. However, I think that concern is
unwarranted given this effects just the tree optimizers, which are not
nearly as pessimistic at block boundaries as their RTL cousins.