https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113737
--- Comment #2 from GCC 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:dede174fbb57bdd3e26f322b6096d53edf0089c4 commit r14-8798-gdede174fbb57bdd3e26f322b6096d53edf0089c4 Author: Jakub Jelinek <ja...@redhat.com> Date: Mon Feb 5 10:57:39 2024 +0100 lower-bitint: Remove single label _BitInt switches [PR113737] The following testcase ICEs, because group_case_labels_stmt optimizes switch (a.0_7) <default: <L6> [50.00%], case 0: <L7> [50.00%], case 2: <L7> [50.00%]> where L7 block starts with __builtin_unreachable (); to switch (a.0_7) <default: <L6> [50.00%]> and single label GIMPLE_SWITCH is something the switch expansion refuses to lower: if (gimple_switch_num_labels (m_switch) == 1 || range_check_type (index_type) == NULL_TREE) return false; (range_check_type never returns NULL for BITINT_TYPE), but the gimple lowering pass relies on all large/huge _BitInt switches to be lowered by that pass. The following patch just removes those after making the single successor edge EDGE_FALLTHRU. I've done it even if !optimize just in case in case we'd end up with single case label from earlier passes. 2024-02-05 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/113737 * gimple-lower-bitint.cc (gimple_lower_bitint): If GIMPLE_SWITCH has just a single label, remove it and make single successor edge EDGE_FALLTHRU. * gcc.dg/bitint-84.c: New test.
