------- Comment #9 from dnovillo at gcc dot gnu dot org 2006-12-13 23:50 -------
The memory problem is quite simple: We just have a *lot* of pointers and a *lot* of addressable symbols. Here is a breakdown of what happens on the first call to compute_may_aliases: During the first call to compute_may_aliases: 1- Size of cc1plus is 339Mb 2- Call to compute_points_to_sets grows to 355Mb (+4.72%) 3- Call to compute_flow_insensitive_aliasing grows to 364Mb (+2.54%) 4- Call to compute_flow_sensitive_aliasing grows to 667Mb (+83.2%) The reason for this tremendous growth is quite simple. There are 39,010 SSA name pointers and many of them have their own points-to set, which we store in that name's may-alias set. We grow to 667Mb in the last loop of compute_flow_sensitive_aliasing. One thing we could do is just not use flow-sensitive information in these cases. If we don't set SSA_NAME_PTR_INFO, everything will default to flow-insensitive information and things will Just Work. Perhaps using sparse bitmaps for the may-alias sets might help with memory consumption, but I found these bitmaps to slow down the operand scanner quite a bit in the past. May be worth a try. Danny, thoughts? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30089
