https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99033
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-9 branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:d1eaf74ee3ac503576e2830e77505cce1ee56e8d commit r9-9419-gd1eaf74ee3ac503576e2830e77505cce1ee56e8d Author: Jakub Jelinek <ja...@redhat.com> Date: Thu Feb 11 17:24:17 2021 +0100 c++: Fix zero initialization of flexible array members [PR99033] array_type_nelts returns error_mark_node for type of flexible array members and build_zero_init_1 was placing an error_mark_node into the CONSTRUCTOR, on which e.g. varasm ICEs. I think there is nothing erroneous on zero initialization of flexible array members though, such arrays should simply get no elements, like they do if such classes are constructed (everything except when some larger initializer comes from an explicit initializer). So, this patch handles [] arrays in zero initialization like [0] arrays and fixes handling of the [0] arrays - the tree_int_cst_equal (max_index, integer_minus_one_node) check didn't do what it thought it would do, max_index is typically unsigned integer (sizetype) and so it is never equal to a -1. What the patch doesn't do and maybe would be desirable is if it returns error_mark_node for other reasons let the recursive callers not stick that into CONSTRUCTOR but return error_mark_node instead. But I don't have a testcase where that would be needed right now. 2021-02-11 Jakub Jelinek <ja...@redhat.com> PR c++/99033 * init.c (build_zero_init_1): Handle zero initialiation of flexible array members like initialization of [0] arrays. Use integer_minus_onep instead of comparison to integer_minus_one_node and integer_zerop instead of comparison against size_zero_node. Formatting fixes. * g++.dg/ext/flexary38.C: New test. (cherry picked from commit ea535f59b19f65e5b313c990ee6c194a7b055bd7)
