On Thu, Sep 11, 2008 at 10:38 AM, Thomas A.M. Bernard <[EMAIL PROTECTED]> wrote: > Hi, > > I inserted some extra instructions in the Alpha back-end (MD files). They > are properly emitted when the flag -O0 is enabled. Since they have no side > effects and no dependencies on other instructions, they are omitted when > flag -O1 is engaged. Is there a way (I mean attribute/constraint in their MD > patterns) to avoid that and keep the extra instructions in any case ?
Depends on how you modeled your instructions. You could use unspec_volatile, but if you modeled "normal" instructions, you have to somehow make the side-effects of your instructions clear. Otherwise, dead code elimination will just remove the instructions (no dependencies -> dead). But you'd have to show what you're doing and what you're trying to achieve, exactly, for a more helpful answer ;-) Gr. Steven
