[Bug tree-optimization/103168] Value numbering for PRE of pure functions can be improved

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103168

--- Comment #17 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
Created attachment 51853
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51853&action=edit
Updated patch

Patch attached.  Indeed the oracle ICEs on ref=base=NULL. I also checked that
during cc1plus build we eliminate 187 calls.