http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58039
--- Comment #5 from Mikael Pettersson <mikpe at it dot uu.se> --- (In reply to Alexander Barkov from comment #4) > > The > > vectorizer turns those into larger and still mis-aligned `movdqa' stores, > > which x86 does not allow, hence the SEGV. > > Can you please clarify: is it a bug in the recent gcc versions? > > Note, we've used such performance improvement tricks for years. > It worked perfectly fine until now. > Has anything changed in how the gcc vectorizer works recently? I know next to nothing about the vectorizer, so I cannot comment on this. > Unfortunately it's not possible to avoid mis-aligned stores due to the > project architecture. Mis-aligned accesses are Ok, as long as they are expressed using the proper mechanisms (memcpy, attribute packed, or pragma packed). > I've read somewhere that gcc vectorizer generates two code branches, > for aligned memory and for non-aligned memory (but can't find > the reference now). Can you please confirm this? I don't know, see above.
