http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47427
--- Comment #3 from rguenther at suse dot de <rguenther at suse dot de> 2011-01-24 12:59:58 UTC --- On Mon, 24 Jan 2011, jakub at gcc dot gnu.org wrote: > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47427 > > Jakub Jelinek <jakub at gcc dot gnu.org> changed: > > What |Removed |Added > ---------------------------------------------------------------------------- > CC| |hubicka at gcc dot gnu.org, > | |jakub at gcc dot gnu.org > > --- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-01-24 > 12:50:47 UTC --- > I think this is pretty much the same issue as PR47428, except in this case it > is not a PHI in which such a replacement is made, but for y_9 = 0; given that > y > is argument declared const the inliner replaces it with 1 = 0;. > So perhaps the PR47428 patch isn't the right fix. copyrename shouldn't do this (coalesce to TREE_READONLY vars - it also doesn't seem to not coalesce to TREE_THIS_VOLATILE vars, though those shouldn't be in SSA form). > The reason why y_9 is on the LHS of a set is copyrename. I guess a fix could > be either not doing copyrename if an SSA_NAME of a TREE_READONLY var would be > on the LHS of an assignment or result of a PHI, or drop the TREE_READONLY from > the parameter in such a case (but that would result in us dropping such info > in > debug info), or avoid the optimization > /* If the parameter is never assigned to, has no SSA_NAMEs created, > we would not need to create a new variable here at all, if it > weren't for debug info. Still, we can just use the argument > value. */ > if (TREE_READONLY (p) > ... > in setup_one_parameter. > > Richard/Honza, what do you think? Fix copyrename. Richard.
