On Wed, 19 Sep 2012, Chris Wilson <chris at chris-wilson.co.uk> wrote: > On Wed, 19 Sep 2012 11:12:41 +1000, Dave Airlie <airlied at gmail.com> wrote: >> From: Dave Airlie <airlied at redhat.com> >> >> We hit this a lot with i915 and although we'd like to engineer things to hit >> it a lot less, this commit at least makes it consume a few less cycles. >> >> from something containing >> movzwl 0x0(%rip),%r10d >> to >> add %r8,%rdx >> >> I only noticed it while using perf to profile something else. >> >> Signed-off-by: Dave Airlie <airlied at redhat.com> > Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk> > > I would have thought this is something the compiler should, with the > appropriate hints, be smart enough to decide for itself as boot_cpu_data > should be constant once defined. *shrug*
Since it's not obvious the compiler isn't smart enough, should the code carry a comment so we don't forget? BR, Jani.
