On Mon, Mar 2, 2015 at 6:34 AM, Aldy Hernandez <al...@redhat.com> wrote: > As I mention in the PR... > > What's happening here is that the ipa_polymorphic_call_context constructor > is calling walk_ssa_copies on a PHI node that has no arguments. This > happens because finalize_jump_threads eventually removes some PHI arguments > as it's redirecting some edges, leaving a PHI with no arguments: > > SR.33_23 = PHI <> > > This should get cleaned up later, but the IPA polymorphic code gets called > during the actual CFG clean-up, and walk_ssa_copies cannot handle an empty > PHI. > > Approved by Honza. > > Fully tested on x86-64 Linux and verified that the patch fixes the ICE on an > x86-64 Linux cross aarch64-linux-gnu cc1plus. > > Committed to mainline.
I think the real issue is that the walking code is executed via fold_stmt when called with an API that tells you not to walk SSA use-def chains. Richard.
