------- Comment #12 from iano at apple dot com 2006-08-22 02:05 ------- "That however is not a clear bug. -ffinite-math-only says that it assumes that there are no NaNs in the input, and you violated that assumption, so the results you will get are undefined. That is, gcc is allowed to give you any answer here. One can argue that the documentation could be improved to indicate this. One could perhaps also argue that this feature is poorly designed. One can't argue that this is an obvious bug."
Let's go with your interpretation for a moment here: If -ffinite-math-only says that it "assumes that there are no NaNs in the input" , then it should not return a result saying that there are NaNs there. I don't think the results here are undefined. I think the results are pretty clear. This is a bug. But, yes, you are mostly right. I want something very feature-ish. I would like you to fix/clarify the design you already have in a direction that works well for users. I would like those builtins (or maybe some other hypothetical future builtins) to function correctly all the time, no matter what. In that regard, I think that the fact that __builtin_isunordered() does the right thing in that particular case is pretty nifty. I just can't depend on it, so it's a useless behavior. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28796
