On 2/03/2012, at 1:53 AM, Martin Jambor wrote: > Hi, > > the following patch backports 4.5 behavior to 4.4 IPA-CP > initialization when it decides which nodes need to be duplicated (we > often say cloned, but cloning is an overloaded term in gcc) in order > to modify them. In 4.5, this is decided by a new predicate called > cgraph_only_called_directly_p which checks both node->needed and > node->local.externally_visible, whereas 4.4 looks only at the needed > flag. > > As described in the PR, this wrecks havoc for ipcp_update_callgraph > which is the stage of the old IPA-CP when it undoes its decisions > which turned out not to be safe. > > Bootstrapped and tested on x86_64-linux, OK for the branch? > > ... > Index: gcc/ipa-cp.c > =================================================================== > --- gcc/ipa-cp.c (revision 184662) > +++ gcc/ipa-cp.c (working copy) > @@ -508,7 +508,7 @@ ipcp_initialize_node_lattices (struct cg > > if (ipa_is_called_with_var_arguments (info)) > type = IPA_BOTTOM; > - else if (!node->needed) > + else if (!node->needed && !node->local.externally_visible) > type = IPA_TOP; > /* When cloning is allowed, we can assume that externally visible functions > are not called. We will compensate this by cloning later. */
Because this is for a branch, I would be more conservative and avoid any new instances of IPA_TOP -- those that can be obtained from subsequent else-if clauses. I.e., else if (!node->needed) type = !node->local.externally_visible ? IPA_TOP : IPA_BOTTOM; Thanks, -- Maxim Kuvyrkov CodeSourcery / Mentor Graphics
