On Wed, Apr 14, 2021 at 06:42:33PM +0100, Richard Sandiford wrote: > Otherwise this looks good apart from the open question about whether > we should be doing complex combinations involving hard regs. Let's see > what Segher says about that side.
It works find with pseudos as well, but then you need to use the same pseudo twice in here. Before RA you cannot know this will be the same hard reg (and it is a bad idea in general to force that). Disallowing forwarding hard regs (from function args) in combine helps quite a bit on average, but there are cases like this one where the balance swings the other way :-( Segher
