On 07/19/2016 04:46 PM, Segher Boessenkool wrote:
But you need the profile to make even reasonably good decisions.
I'm not worried about making cost decisions: as far as I'm concerned it's perfectly fine for that. I'm worried about correctness - you can't validly save registers inside a loop. So IMO there needs to be an additional cfg-based check that verifies whether the bb where we want to place parts of the prologue is guaranteed to be executed at most once.
Bernd
