https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85057
--- Comment #5 from Moritz Kreutzer <mokreutzer at gmail dot com> --- (In reply to Richard Biener from comment #4) > The issue lies in dependence analysis which faces > > _21 = (sizetype) i_24; > _22 = _21 * 8; > _2 = &a + _22; > _13 = MEM[(const Type_t &)&a][i_24].v[0]; > _14 = _13 * 5.0e-1; > MEM[(double &)_2] = _14; > > marks the two refs for a runtime alias test and then when doing that > figures they always alias (but doesn't handle the distance == 0 case > specially). But then I still don't understand how adding the dummy loop helps GCC in determining the independence of loop iterations. > > This is a dup of another existing bug that dependence analysis doesn't > cope very well with a mix of pointer vs. array accesses. Are you talking about 65206? Seems like it's not an easy bug to fix? Anyways, I hope it helps to have proof of another manifestation of this bug...
