------- Comment #13 from mark at codesourcery dot com 2005-10-11 14:47 ------- Subject: Re: [4.0 regression] mem_fun* code fine with -O1, bus error with -O2
ebotcazou at gcc dot gnu dot org wrote: > ------- Comment #12 from ebotcazou at gcc dot gnu dot org 2005-10-11 14:41 > ------- > >>This certainly is a bug in the back-end, not a bug in the default >>location of the v-bit. You shouldn't need to break the C++ ABI on SPARC >>to fix this bug. > > > Right, I was confused, I thought __pfn was dereferenced itself. > > >>However, I'm not sure why you're seeing a 4-byte load from an unaligned >>address. > > > Because p is a pointer to Class and Class has alignment 1. I guess the first > branch of the expression works when Class contains a pointer to the vtable, > hence has alignment 4. Ah. I think that would best be fixed in the front-end, then. If the class doesn't have a virtual pointer, then there's no need to generate the conditional expression; avoiding that will not only fix this bug, but make the code generated by the front-end easier for the middle end to process. Please re-assign to me. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23585
