This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: CSE not combining equivalent expressions.
On Thu, 2007-01-18 at 09:41 +0100, Steven Bosscher wrote:
> There appear to be more bit operations in RTL, so perhaps it is a
> better idea to implement a known-bits propagation pass for RTL, with
> the new dataflow engine.
If that's the case then most of the opportunities are appearing due to
lowering of the IL which would make a lot of sense for detecting
useless sign/zero extensions.
I'm not immediately aware of too many cases where lowering the IL is
going to expose new opportunities to track and optimize nonzero/zero
bits stuff.
Jeff