search for: d8d7aa61

...)); >> X = Y; >> for (i=0, p=(char *)&X; i<sizeof(struct x); i++, p++) >> if (*p != 22) >> abort(); >> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20080311/d8d7aa61/attachment.html>

I thought pointer referencing like this was only valid for arrays. I could be wrong, but it might be that looping over the struct like that is invalid, making it undefined behavior (and then the hole doesn't matter because there is no valid way to access it). That said, I've definitely seen a lot of code that uses pointers to reference struct contents. On Mar 11, 2008, at 10:42

Looking through the gcc testsuite turned up an interesting edge case. Let's assume our target leaves a hole for alignment in struct x, as do x86 and powerpc. Do you think the following code can validly abort? struct x { char c; short s; }; int i; char *p; memset(&X, 0, sizeof(struct x)); memset(&Y, 22, sizeof(struct x)); X = Y; for (i=0, p=(char *)&X;