> > > > On Thu, Oct 09, 2014 at 09:04:49AM +0000, Yangfei (Felix) wrote: > > > > > On Wed, Oct 08, 2014 at 11:00:24PM +0800, Felix Yang wrote: > > > > > The enclosed patch for 4.8 & 4.9 branch is a backport of r211885 > > > > > from > > trunk. > > > > > > > > > > The only change is to use: > > > > > > > > > > for (def_rec = DF_INSN_INFO_DEFS (insn_info); *def_rec; > > > > > def_rec++) > > > > > > > > > > other than the new FOR_EACH_INSN_INFO_DEF interface. > > > > > > > > > > Bootstrapped on x86_64-SUSE-Linux for both branches. OK to apply? > > > > > > > > ChangeLog entry is missing, plus description why do you want to > > > > backport > > it. > > > > If it fixes a bug on the branches, it would be better to have a > > > > bugzilla PR for that, and definitely a testcase. > > > > > > > > > > Yeah, I will add a ChangeLog entry for this patch when it is committed. > > > I encountered the same issue when working on my local customized > > > 4.8/4.9 > > branches. Not reproduceable with the official 4.8/4.9 branches. > > > I thinks it's just an enhancement for the loop invariant pass to > > > make it more > > versatile. It's better that 4.8/4.9 branches also inlcude this enhancement. > > > OK? > > > > If it is just an enhancement, then those generally are not backported > > to release branches (exceptions possible of course, but there needs to be a > strong reason). > > Each pass has some risk of breaking something, exposing previously > > only latent bugs in later passes etc. > > > > Jakub > > We can treat it as bugfix, as we got incorrect code when it triggers. > It just happens so rarely. Does it worth backporting?
And the patch fix this bug by making the loop invariant pass more conservative. I didn't find a PR or testcase on trunk for this patch either.
