Andrew Haley <[EMAIL PROTECTED]> writes: > > > keating> Because if you *do* try to inline the call, you will get an ICE. > > > > Yes, I agree that the ICE, if it still exists, would have to be fixed, > > but to me that seems like a separate issue. > > No, it isn't a separate issue. We generate an abort rather than > ICEing.
My point is simply that the ICE is from a completely different part of the compiler than the point where we insert the trap. > > > We could allow this iff someone fixes the ICE. But we've > > > provided a union cast to do the work if it's *really* needed; > > > insn't that enough? > > > > I don't think gcc should go down the path of inserting trap calls for > > all undefined code. > > That is a pretty outrageous strawman. Nobody has suggested anything > like that. I apologize for presenting something which appears to be a strawman argument. That would never be my intent. Let me restate: I don't think gcc should ever insert a trap call for undefined code. We should only insert a trap call for code which will provably trap. > > That is reasonable if there is nothing else that can be done. But > > in this case there is something easy to do: compile the function > > call as directed. > > If indeed that's easy to do, yes. But I'm pretty confident the abort > wouldn't have been inserted if that were the case. When I read the original e-mail thread that did not seem to be the case. > If we're going to guarantee this stuff for the future, we'll have to > fix the bug, make sure it's doesn't destabilize the compiler and write > some test cases. If we're really serious about it we should make it a > documented extension to C. I'm not exactly opposed to that, but I do > wonder if it's the best use of people's time. But this is free > software, and people choose their own priorities. We're currently breaking an existing free software program which formerly worked although it relied on undefined behaviour. Therefore, I think that changing this would not be a complete waste of time. Obviously I would never ask anybody else to work on it. I personally don't agree that this needs to be a documented extension. I'm simply going on a more general rule which I tried to state above: I don't think we should insert a trap call for undefined code. Ian
