https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88529
--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jason Merrill <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:7232f7c4c2d727431096a7ecfcf4ad4db71dcf2a commit r12-1702-g7232f7c4c2d727431096a7ecfcf4ad4db71dcf2a Author: Jason Merrill <ja...@redhat.com> Date: Sun Jun 13 14:00:12 2021 -0400 expand: empty class return optimization [PR88529] The x86_64 psABI says that an empty class isn't passed or returned in memory or registers, so we shouldn't set %eax in this function. The df-scan hunk catches the case where we look at a 0-length reg and build a range the length of unsigned int, which happened before I changed assign_parms to match expand_function_end. PR target/88529 gcc/ChangeLog: * df-scan.c (df_ref_record): Check that regno < endregno. * function.c (assign_parms, expand_function_end): Do nothing with a TYPE_EMPTY_P result. gcc/testsuite/ChangeLog: * g++.target/i386/empty-class1.C: New test.
