https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104557
--- Comment #3 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:1c2b44b52364cb5661095b346de794bc7ff02866 commit r12-7275-g1c2b44b52364cb5661095b346de794bc7ff02866 Author: Jakub Jelinek <ja...@redhat.com> Date: Thu Feb 17 11:14:38 2022 +0100 valtrack: Avoid creating raw SUBREGs with VOIDmode argument [PR104557] After the recent r12-7240 simplify_immed_subreg changes, we bail on more simplify_subreg calls than before, e.g. apparently for decimal modes in the NaN representations we almost never preserve anything except the canonical {q,s}NaNs. simplify_gen_subreg will punt in such cases because a SUBREG with VOIDmode is not valid, but debug_lowpart_subreg wants to attempt even harder, even if e.g. target indicates certain mode combinations aren't valid for the backend, dwarf2out can still handle them. But a SUBREG from a VOIDmode operand is just too much, the inner mode is lost there. We'd need some new rtx that would be able to represent those cases. For now, just punt in those cases. 2022-02-17 Jakub Jelinek <ja...@redhat.com> PR debug/104557 * valtrack.cc (debug_lowpart_subreg): Don't call gen_rtx_raw_SUBREG if expr has VOIDmode. * gcc.dg/dfp/pr104557.c: New test.
