On 06/11/14 04:05, Zhenqiang Chen wrote:
On 10 June 2014 19:06, Steven Bosscher <stevenb....@gmail.com> wrote:
On Tue, Jun 10, 2014 at 11:22 AM, Zhenqiang Chen wrote:
Hi,
For loop2-invariant pass, when flag_ira_loop_pressure is enabled,
function gain_for_invariant checks the pressures of all register
classes. This does not make sense since one invariant might impact
only one register class.
The patch enhances functions get_inv_cost and gain_for_invariant to
check only the register pressure of the invariant if possible.
This patch may work for targets with more-or-less orthogonal reg
classes, but not if there is a lot of overlap between reg classes.
Yes. I need check the overlap between reg classes.
Patch is updated to check all overlap reg classes by reg_classes_intersect_p:
Just so I'm sure I know what you're trying to do.
You want to map the pseudo back to its likely class(es) then look at how
those classes (and only those classes) would be impacted from a register
pressure standpoint if the pseudo was hoisted as an invariant?
This is primarily achieved by returning the class of the invariant, then
filtering out any non-intersecting classes in gain_for_invariant, right?
jeff
