On 02/26/2016 08:41 AM, Bernd Schmidt wrote:
On 02/22/2016 03:37 PM, Richard Biener wrote:
Do calls properly clobber them even if they are not in the set of
call-clobbered regs?
Are asm()s properly using/clobbering them? I think you are allowed to
use them
in asm()s without adding constraints for them?
Calls do, asms currently don't AFAICT. Not sure whether it's allowed to
use them, but I think it should be straightforward to adjust df-scan.
The other case that came to mind was signal handlers. What happens if
we're using the global register as a scratch, we hit a memory reference
that faults and inside the signal handler the original code expects to
be able to use the global register the user set up?
If that's a valid use scenario, then there's probably all kinds of DF
stuff that we'd need to expose.
jeff
