https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94716
--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:91031bffa42fdea3c985727d042cd1882a64be9c commit r12-6188-g91031bffa42fdea3c985727d042cd1882a64be9c Author: Jakub Jelinek <ja...@redhat.com> Date: Mon Jan 3 13:47:53 2022 +0100 symtab: Fold &a == &b to 0 if folding_initializer [PR94716] On Thu, Dec 09, 2021 at 06:09:12PM -0500, Jason Merrill wrote: > For the more general comparison of decls like your a != b example above I > think clang is in the right; in manifestly constant-evaluated context > (folding_initializer) we should return that they are unequal and prevent a > later alias declaration, like we do for comparison to 0 in > maybe_nonzero_address. It's possible that this gives a wrong answer based > on something in another translation unit, but that's unlikely, and taking > that chance seems better than rejecting code that needs a constant answer. I agree. This is an incremental patch to do that. 2022-01-03 Jakub Jelinek <ja...@redhat.com> PR c++/94716 gcc/ * symtab.c: Include fold-const.h. (symtab_node::equal_address_to): If folding_initializer is true, handle it like memory_accessed. Simplify. gcc/testsuite/ * gcc.dg/init-compare-1.c: New test. * g++.dg/cpp0x/constexpr-compare1.C: New test. * g++.dg/cpp1y/constexpr-94716.C: New test. * g++.dg/cpp1z/constexpr-compare1.C: New test.
