https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80755
--- Comment #7 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Lewis Hyatt <lhy...@gcc.gnu.org>: https://gcc.gnu.org/g:6c166e55b15894ceb07dcc7b55f900e50e24ec5b commit r14-9464-g6c166e55b15894ceb07dcc7b55f900e50e24ec5b Author: Lewis Hyatt <lhy...@gmail.com> Date: Wed Dec 20 16:27:42 2023 -0500 libcpp: Fix __has_include_next ICE in the last directory of the path [PR80755] In libcpp/files.cc, the function _cpp_has_header(), which implements __has_include and __has_include_next, does not check for a NULL return value from search_path_head(), leading to an ICE tripping an assert when _cpp_find_file() tries to use it. Fix it by checking for that case and silently returning false instead. As suggested by the PR author, it is easiest to make a testcase by using the -idirafter option. To enable that, also modify the dg-additional-options testsuite procedure to make the global $srcdir available, since -idirafter requires the full path. libcpp/ChangeLog: PR preprocessor/80755 * files.cc (search_path_head): Add SUPPRESS_DIAGNOSTIC argument defaulting to false. (_cpp_has_header): Silently return false if the search path has been exhausted, rather than issuing a diagnostic and then hitting an assert. gcc/testsuite/ChangeLog: * lib/gcc-defs.exp (dg-additional-options): Make $srcdir usable in a dg-additional-options directive. * c-c++-common/cpp/has-include-next-2-dir/has-include-next-2.h: New test. * c-c++-common/cpp/has-include-next-2.c: New test.