Hi, On Tue, 22 May 2012, Richard Guenther wrote:
> > I had thought of that as well. But it is not quite that simple -- the > > problem is that tree-ssa-reassoc.c as part of its core algorithm > > reassociates > > expressions all the time while even still building up the tree, see e.g. > > linearize_expr or break_up_subtract. Those steps may all be invalid in > > general, but we only know whether that is true at the very end, once we've > > built up the full tree -- but at that point it is already too late. > > Hmm, really? Yep, reassoc rewrites already at linearize time. I think that could be changed without too much hassle. > I had not realized it does something it cannot undo later ... > but well ISTR patches floating around for re-organizing how we do > the break_up_subtract / negate stuff. Micha? Yes, I have an incomplete patch for that, but it didn't touch the current fundamental implementation detail of tree-reassoc, namely touching statements at analyze time already. Ciao, Michael.
