>>> I guess, such a large positive index in GEP as seen above can be >>> introduced by -instcombine pass. >> >> Ok. This is somewhat dubious though, as it is wrapping around the >> end >> of the address space which is undefined in C. > > I've found one place in instcombine, where something like this can be > introduced. Fixed with this patch: > http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of- > Mon-20071210/056253.html
I agree, that is definitely an instcombine bug, thanks! >>> I think, the simplest way to fix it is to truncate the computed >>> offset >>> to the target pointer size before returning it in >>> TargetData::getIndexedOffset(). If you think this is the correct >>> approach, I may prepare a patch. >> >> Ah, that does make a lot of sense. Since the fix is simple, >> please go >> for it! > > I've rethought the issue. If you say that, wrapping around the > memory by > getelementptr is undefined, I think it's better to leave it as it is. > This way we'll be able to catch other optimizer bugs, if there are any > of the above kind. Excellent, thanks! -Chris _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
