On 08/02/2011 05:22 AM, Richard Guenther wrote: >> -fno-tree-ter also unbreaks the ARM test case in PR48863 comment #4. > > It's of course only a workaround, not a real fix as nothing prevents > other optimizers from performing the re-scheduling TER does. > > I suggest to amend the documentation for local call-clobbered register > variables to say that the only valid sequence using them is from a > non-inlinable function that contains only direct initializations of the > register variables from constants or parameters. > > Or go one step further and deprecate local register variables alltogether > (they IMHO don't make much sense, and rather the targets should provide > a way to properly constrain asm inputs and outputs).
Neither of these is a viable option. What we might be able to do is throttle TER when the destination is a local register variable. This should unbreak the common case of local regs immediately surrounding an asm. r~
