https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112918
--- Comment #16 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Vladimir Makarov <vmaka...@gcc.gnu.org>: https://gcc.gnu.org/g:a729b6e002fe76208f33fdcdee49d6a310a1940e commit r14-7141-ga729b6e002fe76208f33fdcdee49d6a310a1940e Author: Vladimir N. Makarov <vmaka...@redhat.com> Date: Thu Jan 11 08:46:26 2024 -0500 [PR112918][LRA]: Fixing IRA ICE on m68k Some GCC tests on m68K port of LRA is failed on `maximum number of generated reload insns per insn achieved`. The problem is in that for subreg reload LRA can not narrow reg class more from ALL_REGS to GENERAL_REGS and then to data regs or address regs. The patch permits narrowing reg class from reload insns if this results in successful matching of reg operand. This is the second version of the patch to fix the PR. This version adds matching with and without narrowing reg class and preferring match without narrowing classes. gcc/ChangeLog: PR rtl-optimization/112918 * lra-constraints.cc (SMALL_REGISTER_CLASS_P): Move before in_class_p. (in_class_p): Restrict condition for narrowing class in case of allow_all_reload_class_changes_p. (process_alt_operands): Try to match operand without and with narrowing reg class. Discourage narrowing the class. Finish insn matching only if there is no class narrowing. (curr_insn_transform): Pass true to in_class_p for reg operand win.
