------- Comment #3 from dorit at gcc dot gnu dot org 2007-08-31 14:18 ------- (In reply to comment #2) > Subject: Re: Missed opportunities for vectorization due to invariant > condition > > Looks like -fno-tree-pre is not enough, because if PRE doesn't do it, then > > sink > > does it. When I use "-O3 -ftree-vectorize -msse2 -fno-tree-pre > > -fno-tree-sink" > > I get the dataref problem you report below, without manual modifications to > > the > > code > > > Apparently this is sink is triggered on -O3, Daniel also warned yesterday > about the fact that it's not PRE specific. > Actually, can't we move that code back in the loop body when > the vectorizer detects that code in the latch bb?
here's a related discussion from a couple years ago: http://gcc.gnu.org/ml/gcc-patches/2005-11/msg02045.html (and also a somewhat related PR - PR28643) > I'm thinking that it is not really difficult to consider these scalars > as arrays with a single element, and then just pass these to the rest > of data deps. I'll try to figure out a patch for this problem that would > bring us more vectorized cases. great. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33245
