------- Comment #9 from law at redhat dot com 2010-01-12 15:18 ------- Subject: Re: vectorizer created unaligned vector insns
On 01/12/10 01:08, irar at il dot ibm dot com wrote: > ------- Comment #8 from irar at il dot ibm dot com 2010-01-12 08:08 ------- > So, to be on the safe side, we should assume that COMPONENT_REFs are not > naturally aligned and never use peeling for them? > If you can not *prove* at compile time that you're going to get the proper alignment, then you can't vectorize without a runtime check to select between a vectorized and unvectorized loop. Proven alignement -- vectorize Proven unaligned -- do not vectorize Likely aligned, but not proven -- emit two loops, one vectorized, one not vectorized and runtime selection of the proper loop Otherwise you run the risk of making conforming code segfault which is obviously unacceptable. jeff -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42652
