https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112701
--- 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:ce52f1f7074d96c4d9ce63b1169c11087757e926 commit r14-5898-gce52f1f7074d96c4d9ce63b1169c11087757e926 Author: Lewis Hyatt <lhy...@gmail.com> Date: Mon Nov 27 12:08:41 2023 -0500 libcpp: Fix unsigned promotion for unevaluated divide by zero [PR112701] When libcpp encounters a divide by zero while processing a constant expression "x/y", it returns "x" as a fallback. The value of the fallback is not normally important, since an error will be generated anyway, but if the expression appears in an unevaluated context, such as "0 ? 0/0u : -1", then there will be no error, and the fallback value will be meaningful to the extent that it may cause promotion from signed to unsigned of an operand encountered later. As the PR notes, libcpp does not do the unsigned promotion correctly in this case; fix it by making the fallback return value unsigned as necessary. libcpp/ChangeLog: PR preprocessor/112701 * expr.cc (num_div_op): Set unsignedp appropriately when returning a stub value for divide by 0. gcc/testsuite/ChangeLog: PR preprocessor/112701 * gcc.dg/cpp/expr.c: Add additional tests to cover divide by 0 in an unevaluated context, where the unsignedness still matters.
