https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99751
--- Comment #9 from Jan Hubicka <hubicka at gcc dot gnu.org> --- OK, so actually there is logic to handle return values (even for consts) but it has wrong if. I am testing the attached fix. diff --git a/gcc/ipa-modref.c b/gcc/ipa-modref.c index 7aaf53be8f4..5f33bb5b410 100644 --- a/gcc/ipa-modref.c +++ b/gcc/ipa-modref.c @@ -1545,9 +1545,9 @@ merge_call_lhs_flags (gcall *call, int arg, int index, bool deref, tree lhs = gimple_call_lhs (call); analyze_ssa_name_flags (lhs, lattice, depth + 1, ipa); if (deref) - lattice[index].merge (lattice[SSA_NAME_VERSION (lhs)]); - else lattice[index].merge_deref (lattice[SSA_NAME_VERSION (lhs)], false); + else + lattice[index].merge (lattice[SSA_NAME_VERSION (lhs)]); } /* In the case of memory store we can do nothing. */ else @@ -1621,7 +1621,7 @@ analyze_ssa_name_flags (tree name, vec<modref_lattice> &lattice, int depth, else if (gcall *call = dyn_cast <gcall *> (use_stmt)) { tree callee = gimple_call_fndecl (call); - /* Return slot optiomization would require bit of propagation; + /* Return slot optimization would require bit of propagation; give up for now. */ if (gimple_call_return_slot_opt_p (call) && gimple_call_lhs (call) != NULL_TREE