Hi, Profiledbootstrap fails with ICE in update_loop_exit_probability_scale_dom_bbs called from loop unroling. The reason is that under relatively rare situations, we may run into case where loop has multiple exits and all are considered as likely but then we scale down the profile and one of the exits becomes unlikely.
We pass around unadjusted_exit_count to scale exit probability correctly. In this case we may end up using uninitialized value and profile-count type intentionally bombs on that. Profiledbootstrapped x86_64-linux, comitted. gcc/ChangeLog: PR bootstrap/110857 * cfgloopmanip.cc (scale_loop_profile): (Un)initialize unadjusted_exit_count. diff --git a/gcc/cfgloopmanip.cc b/gcc/cfgloopmanip.cc index 86360b5f380..b237ad4e8ac 100644 --- a/gcc/cfgloopmanip.cc +++ b/gcc/cfgloopmanip.cc @@ -742,7 +742,7 @@ scale_loop_profile (class loop *loop, profile_probability p, /* In a consistent profile unadjusted_exit_count should be same as count_in, however to preserve as much of the original info, avoid recomputing it. */ - profile_count unadjusted_exit_count; + profile_count unadjusted_exit_count = profile_count::uninitialized (); if (exit_edge) unadjusted_exit_count = exit_edge->count (); scale_loop_frequencies (loop, scale_prob);